Fweeeeeeeeeeeeeeeh ....
Ya know, I also wondered why Bubbles hasn't been venting coolant lately.
We've seen Roko and Bubbles vent (can't recall any other AI venting offhand... maybe Momo when she ran into Sven?) and I think they might only vent when they're
conflicted, or are at least temporarily unable to choose the next words or actions - they literally have processors or banks of processors running in opposite directions or looping back and forth or something, so there's some local overheating while the processors work frantically to sort it out. Or something like that. Maybe it would be better described as embarrassment (but then again having no idea of your next action is part of being embarrassed.)
Obviously, Bubbles' emotions are at a very high pitch lately, but they're running the same direction. She's certainly not conflicted or unable to choose what to do next, so no venting. (Roko vented pretty hard when Renee called her out on her bread fetish; she embarrassed and at a loss as to what to do. Ultimately, she bought a bunch of bread and ran away.)
That's my pet theory about venting, anyway; it's triggered by a specific circumstance or condition, not just strong emotion. We'll see whether it holds up.
Just one of those nerdy little details that's fun to ponder, and makes the AI characters a little more real.