I just realized what was going on with the new mapping for the directional thumb pad on the Tartarus Pro after the latest Razer Synapse update.
It appears the D-pad's directions are now a one-to-one match with a standard keyboard's arrow keys. This means the "Up" direction on the thumb pad now directly corresponds to the "Up" arrow key, "Left" to the "Left" arrow key, and so on.
If you are using custom key bindings for movement (such as WASD), you will likely need to go into your Synapse settings and re-map the D-pad to reflect this new layout. This will help ensure your custom keybinds function as expected.
This is a change that many users are noticing, so remapping your keys is a necessary step to get your device working correctly with your personal settings.