Basilisk Ultimate mouse 4 and 5 glitch... Help?

A few days ago my basilisk ultimate mouse started having an issue where pressing either mouse 4 or mouse 5 registered as having both mouse 4 and mouse 5 pressed simultaneously. I did a few mouse input tests to verify this and normally pressing mouse 4 would output this:

mousedown which=4 button=3 buttons=8
mouseup which=4 button=3 buttons=16

But instead it outputs this:
mousedown which=4 button=3 buttons=8
mousedown which=5 button=4 buttons=24
mouseup which=4 button=3 buttons=16
mouseup which=5 button=4 buttons=0

The same is true for mouse 5. So far I have restarted my computer, the mouse, synapse, reinstalled synapse and all mouse drivers, thoroughly cleaned the mouse and cracks/crevices around the mouse 4 and 5 buttons, and manually editing what mouse 4 and mouse 5 do in synapse as well as reset the mouse to factory settings, all to no avail. Any ideas besides an RMA?