Maybe a conflict with other on text events in that scriptfile?
I did test it again, and it's working as expected:
[Bot] •• horstl
true
[Bot] •• Horstl, test
true
[Bot] •• this shoudnt trigger 123horstl
[Bot] •• Horstl?
true
[Bot] •• works Horstl! (containing control codes in the "nick")
true
