The song Here I Go Again by Whitesnake has a radio mix with different words.
The original had “like a hobo I was born to walk alone”. It was changed to “like a drifter”. Apparently hobo sounded too close to homo.
I’m assuming this is pure UL. Van’s entire career wraps around his repeated refusal to conform and the industry punishing him.
Doing more searching I found this on Wikipedia:
Originally titled “Brown-Skinned Girl”,[11] Morrison changed it to “Brown Eyed Girl” when he recorded it. Morrison remarked on the title change: “That was just a mistake. It was a kind of Jamaican song. Calypso. It just slipped my mind [that] I changed the title.”[12] “After we’d recorded it, I looked at the tape box and didn’t even notice that I’d changed the title. I looked at the box where I’d lain it down with my guitar and it said ‘Brown Eyed Girl’ on the tape box. It’s just one of those things that happen.”[[13 (Brown Eyed Girl - Wikipedia)[14]
As well as this:
Because of a contract he signed with Bang Records without legal advice, Morrison states that he has never received any royalties for writing or recording this song.[16] The contract made him liable for virtually all recording expenses incurred for all of his Bang Records recordings before royalties would be paid.[17] Morrison vented frustration about this unjust contract in his sarcastic nonsense song “The Big Royalty Check”. Morrison has stated that “Brown Eyed Girl” is not among his favourite songs, remarking “it’s not one of my best. I mean I’ve got about 300 songs that I think are better”.[18]
Oh, man. “Drifter” is so much better than “hobo.”
When I was a kid I used to listen to a country station and they dubbed over “I want to hear a love song and dance real slow.”
It was “I want to hear WITL, Best in the country!”
It sounds terrible and I’ve never been able to hear that song without singing it that way.
Fortunately it wasn’t a very memorable song.
On many songs I’ve heard “shit” reversed to “tish”. Really makes it stand out, but not too bad if only done once per song. However, within the past week I heard an edit of My Chemical Romance’s “Teenagers” which changed
Teenagers scare the living shit out of me
to
Teenagers scare the living tish out of me
This is in the chorus, so it repeated many times throughout the song. After about the tenth time I had to change the station, even though that song was kind of a theme song for us - it came out just as my son was a teenager.
Does this make even the slightest shred of sense?! Changing the lyrics at all was lame enough, but that was the best they could do?! LOL
As mentioned upthread, that lyric change appears to be a random live adlib by Buffett which he did that all the time in concert.
Or my mind may be going. However there are other songs that have been confirmed. 
So, he intentionally made the lyrics of his own song sound stupid in front of a live audience? Oh, then it was okay, then. 
He did that all the time. I’m guessing he had a bad sunburn at the time, I don’t think it was meant to be profound.
Just to clarify: the song was originally released in 1982 with the “hobo” line. When they re-recorded the song in 1987, they changed it to “drifter,” for the reason you say.
Bob Dylan did it all the time. He wrote the songs. He knew the lyrics. He’d change the tempo, do extra verses, change a word here or there. If you just want to hear the song as published on a record, stay home and listen.
Imagine how boring it must get singing the same song, night after night.
The story is apparently a little more complex than this.
Whitesnake originally recorded the song in 1982; according to Wikipedia, they had initially used the word “drifter” while writing the song, but then changed it to “hobo” for the 1982 recording – co-writer David Coverdale notes that this was because he’d already used “drifter” on several other songs. That original version was a minor hit in the UK and some other countries, but didn’t chart in the U.S.
Then, in 1987, the band re-recorded the song, in order to re-release it on a new album, and intentionally went back to “drifter” when they re-recorded it, because, as you note, it may have sounded too much like “homo.” That version is the one that became a big hit in the U.S., UK, and elsewhere, at least in part due to the music video.
So, it wasn’t exactly that they had a “radio mix” with the different word, but a re-recording, five years later, contained the changed word on all releases (album, single, video).
I suspect it was just a matter of station policy. Album-oriented rock stations, whose audiences tended to skew more towards adults (and older teens), seemed to be all right with the occasional curse word in a lyric, but top-40 pop stations, which likely tended to have younger audiences, seemed to be more likely to bleep out an objectionable word, replace it, or use a radio-friendly alternate recording by the artist.
Yeah, in my experience, it’s quite common for singers to change lyrics around a little bit to fit the moment/mood/to be funny/etc.
A friend of mine was lead in a blues band in Pittsburgh (until he took his own life. Now that’s the blues). He did lots of covers. Occasionally he’d blank on the lyrics. He’d smoothly transition into scat singing if that fit with the song or he’d sing the alphabet in place of words. Worked well for him.
Yeah, singers forgetting the words to even their own songs and having to ad-lib or just own up to it is also something I’ve seen a lot of. Never heard anyone do the alphabet thing, though. 
The Cardi B. song “WAP” (which stands for “Wet-a** Pssy") is the most sexually explicit (er, implicit) song I’ve heard in a very long time. It has a radio edit that instead uses the phrase “Wet and Gushy.” Every other blush-inducing phrase is the same in the song, except "fcking with” is “messing with” and towards the end she actually says the words “dck" and "fck me” and they’re straight up removed.
This edit of the song makes me laugh, like, who is this censored version for?!
Too, I’ve always assumed that a helpful factor was that it’s not all that obvious. The place where it’s located in the song and way it’s performed, it could easily whoosh right past someone, especially if that person isn’t listening attentively.
But then again, once you hear it, it becomes glaringly obvious.
I’ve heard tell of a DJ who would recite the alphabet at just the right speed during the intro to “Build Me Up Buttercup”:
“…V, W, X-” “WHYYYY DO YOU…”
This is a good point. An early Electric Light Orchestra song, “Oh No Not Susan,” contains the line, “They just don’t mean a fucking thing.” The song got a fair amount of airplay on the BBC, which may have been because the word didn’t actually appear on the lyric sheet, it wasn’t enunciated clearly, and/or the band didn’t go out of their way to point it out.