Changing Chrome Tabs Stopped working

Hi there. Thank you for taking the time to ready. I have a mac and use chrome as my daily browser. I heavily rely on Control + Fn + PgUp and PgDn to switch between tabs.

This stopped working. I tried unplugging and plugging in my keyboard and it works for 3 seconds but then it stops. I am on a older USB only type S and I remapped the control key to the Tab key.

Any idea on what could be causing this?