I'd suggest waiting until 1st October before submitting the bug report.
That'll give about a week (from the time of the original post) for any further feedback:
PM tends to be quieter over the weekend, so there may be more to come.
In your bug report, I'd stick to what you know:
problem on these (list) Perl & Tk combinations; but no problem on these (other list) combinations.
I would avoid conjecture altogether: "I'm pretty sure ..."; "I would expect ..."; and similar.
It's likely that maintainers have their own testing environments:
they can confirm what you report as well as testing other scenarios.
I'd also include a link to this thread: your report can summarise findings; with the link back to here for details.
It shows that you made an effort before raising the bug report.
There may be additional information by the time someone gets around to looking at the problem.