I do not know the reason for this. But, Voyager minimizes once a while like my keyboard is on when its not. I use Futo keyboard and have experienced this bug for a long time across voyager versions. My android version is 15 but I also used to experience this in android 14.
At the time of the screenshot I was using Niagara launcher which could perhaps be related.
You’ve already proven that the version of the operating system isn’t relevant. Try troubleshooting with a different keyboard for a week. If that makes no difference, try a different launcher for a week.