Was playing Onslaught in Unreal Tournament 2004. Had 32 bots and was playing I think it was ONS-Dria and noticed something... off. The opposing team was really aggressive and was pushing real hard while I noticed a lot of my team bots were actually shooting at friendly power nodes that was not with the Link Gun's alt fire. I can't tell if they were passively stupid, but I ended up just cheating to see how hard it was to push back. Turns out I had to spam the super weapons just to make breathing room and the final push was just bombing run after bombing run at the last node. I wonder if the AI just glitched out or I ended up getting a bad roll of the dice and got the less helpful stock of bots.

Anything like this happen to you?

I remember watching about some of the AI's of the past, and UT apparently has no built-in AI. Instead what it will do is the 20-30 seconds before they spawn and while you play it watches you and it generates an AI based on how you act/move, which adds to it's complexity.

It may be possible that you play very well so then the AI will competent enough to challenge you, and at 32 of them, well....

If you want an easier AI, you need to basically do nothing until right before the AI spawns. Or so i heard it suggested. Wish i could remember which video it was that i watched like 7 years ago...

That's not how the AI in UT games works. I assure you that it does have a built-in AI, and quite a complex one at that. No gimmicks with last 20-30 seconds or whatever. The bots spawn in right at the start of the game, there is no delay. You can then add or remove additional bots with commands. You can see the details of each difficulty here:
https://unreal.fandom.com/wiki/Bot

The OP should say what difficulty they played at and whether "Auto Adjust skill" was enabled in the options. That one dynamically adjusts the bot difficulty depending on how well you are doing.

I had them set for adept. Not easy, not too hard, although I've had games where we rolled over them as much as they us, but this and a few other games were disproportionately harder than usual, and one game went on for so long on a stalemate the game straight up crashed.

I distinctly remember playing Unreal Tournament. I think it may have been UT 2002. It has been *quite* some time now.
I remember the game being advertised with an adaptive AI, that could adjust to your playstyle.

And well: I was never able to beat the last opponent in the campaign. I was able to beat him in the first two round, and then he always obliterated me.
But i also never was (and am still not) a good FPS player.