I write, so if someone has the same problem, this post may help. I could not find a single post regarding this situation.
So, I connected 3 IKEA bulbs directly to an Aoetec Hub (the current one) and they always did the same thing: they connect and work fine (setup process is great and fast), work perfectly for 2 or 3 minutes, but then turn on every minute or so on their own (no commands from the hub in the log), change to 4000k and stay on until turned on and off from the app, then, some seconds later, they do it again.
The way I resolved the issue was by connecting all of them at least once with an IKEA remote and afterwards I reset them, connect them again, and they work like a charm! No IKEA hub or Tradfri app necessary.
The only downside I can find is the lack of the “state after power loss” functionality of IKEA’s own hub.
All lights in the screenshot are IKEA color temp bulbs renamed for convenience by me (I google lens searched the names of all my, funnily from IKEA, lamps )