There's nothing improper with adding "Edit: credit to the <name of the person> who suggested the solution. While the solution seems trivial, there are certain technical challenges to overcome".
> because that's where I heard about it first.
No. That's not where you heard it first. Otherwise you wouldn't have written "this needs doctoral research on performance" in the original issue.
Edit: I misattributed this quote, you didn't say it.
> I don't think hearing about it again from Casey
There's an actual, verifiable screenshot of your reaction to his words. That was not an "again".