This software is free and the person behind it has put very very much work into it.

Think of it as a demo version, which works most of the time. Pay and get the full version if you really depend on it.

I can confirm, I just installed the beta (v5.9.0.9) and there is no need for a key.

And the problem itself is solved too.

I'm on version 19041.450 here and the problem is the same.

Should I make my own topic on that or would a fix likely provide a solution for both versions?

This compatibility topic is and will be a reoccurring issue anyhow - which is totally ok - just mentioning it because of a seperate ticket.