I don’t think I’ve ever heard it pronounced any other way than jag-wire/war except by people on tv.
The first time I remember hearing it said using the british pronunciation, it was a local reporter in Savanah GA. I remember thinking someone was playing the hoity toity snob that day.
IANAL
(I’m not a linguist) but my understanding is that apparently the mind can mentally fill in sounds which are close so it may be possible you have heard it before but not be aware of it.
I remember, as a kid, the first time I encountered the word in print and I thought it was a different species of large cats.
I wouldn’t be surprised if that’s happening to me. My ears aren’t all that great anyway, most things sound kind of flat to me, FM doesn’t sound much different than AM. My mind could certainly have filtered out the “wire” because I never expected it.
Jaguar and other British cars used Lucas brand electric components. They were less than perfectly reliable (wallowing neck deep in understatement here), hence various “Lucas” jokes referring to that, this one being about lights that don’t work. Another example is “Why do the English drink warm beer? Because they have Lucas refrigerators.”
Sean Connery ftw
Jagwire: