Hi @rswain ,
Yes, there are two places to improve:
1. empty the string variable VerifyUsers after your condition 3 action:

Just set it to null formula.
2. If the result is still not correct, you can consider using toLower formula to both of the email address in your condition action:

For example, I will use below formula for the group mail dynamic content:
toLower(items('Apply_to_each_2')?['mail'])
which would be toLower(items('Apply_to_each_3')?['mail']) in your flow.
Hope this helps.
Best Regards,
Hen Wang