Razer Viper Ultimate: Right side-buttons only register Right Click

Rattlesnark
Just plugged in a newly purchased Razer Viper Ultimate. I'm facing the issue where the right side-buttons, that by default should function as MB4 and MB5, instead only function as right click, disobeying whatever settings in Synapse.

Pretty much all that I've tried (so far):
1. Plugging my dongle directly into my PC instead of on the charging dock.
2. Connecting the mouse to the PC directly via USB cable.
3. Plugging the dongle/USB cable on different USB ports on my PC.
4. Turning the mouse's power off-and-on.
5. Testing it on my OSX Macbook - different machine with different OS.
6. Switching the mouse to left-hand mode on Synapse. When I do this, the right side-buttons switch to perform LMB click instead.
7. Changing the right side-buttons to different functions on Synapse for my Default profile as well as my alternate profile automated to Discord.
8. Restarting my PC.

I'm hoping Razer Support Chat might offer some insight as well, but I have to wait until tomorrow's opening hours.

EDIT: Embarrassingly, I could very well have been pressing the far right edge of the RMB instead of the side buttons, without looking at my fingers on my mouse. Leaving this message here for posterity.