Thank you for your efforts, Jonny.blue. I had already done exactly these tests. I had installed "Light Control" as the app.
Again, this app is unable to force LM 4 to stay light. But it works with other apps.
In one of my previous posts I said that I wanted to test my daughter-in-law's S 20. Here too, LM 4 darkens.
I am annoyed that some USERS say it is only due to my devices. I claim that if everyone were to test under the same conditions, the problem generally exists with LM 4, otherwise it would be absolutely unlikely that only I would have the problem with the S 6, S 8, S 10, S 20 and S 21 and the Xcover pro even twice (because I replaced the device).
However, I accept that Menion cannot understand the error in the app.
I am now sticking to LM 3 and, as I have already said, I will wait and see if there is anything new on this topic.