Mi LED Smart Bulb Color turns off after minutes and bugs

Even though there are many similar post here, my problem seems to be a bit different.
My Mi Smart LED Bulb Color worked fine for four months, but is now bugging as hell.
It turns off after a few minutes, changes color automatically without touching the app and is sometimes in a weird state between on and off (just a little bit of light, you can clearly see that something is still on inside the lamp).
When I try to set the lamp on clear white, it turns blue, the yellow color does not work at all, it then goes in this weird middle state, so nearly completely off.
I have tried resetting it, used it in a different room, but I got the same results.
The App (Mi Home 6 now) also does weird things and changes automatically between white and color.

I use the Europe Server (I’m from Germany) and the latest firmware 2.0.6_0035, also the latest version of the Mi Home App available in the Play Store.
Is this a hardware issue (which many people are reporting) or a software issue?
Thanks for help!