Bug in Contains assertion with option "Use token as Regular Expression"

Hi all - I think there is a bug in soapUI's contains assertion when using the option "use token as regular expression".

I boiled this down to a case where this doesn't even match a single character which obviously IS contained in the response, but the condition still doesn't match. I reported this issue in another append but got no reaction whatsoever.

What is the suggested way to bring this to the developer's attention and get a response whether this is indeed a bug or what one needs to do or enable to get this feature working?