It was short in the plugin directory in my opinion. This would only be possible if Sergej defined the plugin as GPL. The price model afterwards (?) was always incompatible with the GPL.
The question remains whether it was taken out of the directory to be re-licensed (possible at all?) or just because it violated the GPL.
In any case an unpleasant fact. So any fork would be a legal risk, as long as the new owners don’t understand the strengths of open source and make the plugin GPL themselves.