Update: I looked at my integrations, and there's a second one that I had hooked up to Google Cloud Platform (about 2 years ago, and completely forgot about). The event associated with that was temperature, so I changed the one I'm currently working on to temperature2024. The problem persisted, so I disabled the old integration, and now I'm good.
So, my hypothesis is that the temperature2024 event I was publishing, and connecting to ThingSpeak, somehow was also triggering the temperature event associated with GCP. I don't quite understand why that would be happening, so if anyone could explain I'd be grateful!
The event name used in the integration is meant as a prefix.
So any event starting with temperature (including temperature2024 ) will still be caught by any integration that is looking for temperature