This is a pretty common occurrence for me when traveling. I will go into a bar, look at the menu, and order a drink and some food only to be told that the kitchen is closed. The hours for the kitchen are never listed on the menu or the website. The hours posted by the door are always for the establishment as a whole, and never seem to mention when they are serving food.
Serving food is a money loser for a lot of bars these days. They want to keep their kitchens licensed for special occasions or in some cases as a requirement of a liquor license, but normally they don’t want to keep it stocked with food and have to pay a cook or keep someone with food safety certification around. So they have a kitchen but they don’t want to commit to using it an any particular time.
Sometimes it’s just flexible; several of my old local pubs had a 'kitchen’s open ‘til it’s closed’ attitude. They prepped the food they expected to sell at the start of meal times, when that was sold the cook went home. Some would also close the kitchen because it was too quiet, or open it at odd times because they were expecting the place to be busy (when there was a big match on or something).
I always wondered how they managed to find someone willing to be available with such vague hours, which is probably the other reason they’d be shut; they couldn’t get anyone to work that shift.
I’ve encountered the opposite issue more often: pubs that offer breakfast do not always say when their alcohol service starts. Neither situation has ever had a real world impact, however, I’ve only encountered it when clicking on places websites on Google Maps.
Yeah, food in these places tend to be an afterthought. I’ve heard of one such bar that has exactly one item on their “menu”, don’t recall what but it’s something outrageously expensive and could easily be made at home for much less.