I've seen someone posted about this here, seems to be the same issue I'm having. But there was no clear answer to solve the issue. Is someone else having the problem?
An update, the issue was with my macro itself, and not the Background Mode. So If you're having this issue, just review your macros.
Not sure what's happening, but issue is still ongoing. The same macro works with the game opened, but it bugs at some point while on Background