update: found the solution myself. After I additionally installed the MiHome App the Lightstrip immediately got detected and reinstalled propperly. So the problem was the Yeelight App - which btw now is detecting the Lightstrip again, too - after MiHome detected and reinstalled it.
Thanks for reading!!
Maybe there is device discovery cache at the beginning, pls don't worry about it. BTW, if you select the same locale from Yeelight with mihome, you can also control the light strip from Yeelight.
Android or iOS?
Sorry, I forgot to mention it, it's Android.
Thanks for reading!
Thanks for taking care!!
Everything is working perfectly now. Not sure what the problem was, but it's solved.
Thanks for your advice!!
Glad to know it's working!