That sounds like a bug, would you mind reporting it, ideally with a way to reproduce the issue? Thanks in advance.
Not just alert text, but for (almost) all text there is a method contrasting_text_color . Based on the luminance of the background color, either black or white is used for the foreground text.
PS. For details search for “sRGB luminance” or have a look at the source
It took a while to reproduce but I did narrow it down. And I am challenged by the bug tracker, and have never been able to login. However, one can reproduce the “No Align” warning by connecting the output of a track to a buss and also connect the output to a hardware output (keep it all either L or R to reproduce). For example, mono Track 1 left side goes to left side of mono buss 1. The “No Align” will blink if you also attempt to send Track 1 left side to any hardware output left side.
I don’t think this should raise an error but it does.