Critical Bug in Synapse 4: Unable to remap or disable Sensitivity Stage button on DeathAdder V2 X HyperSpeed

Device: Razer DeathAdder V2 X HyperSpeed Software Version: Razer Synapse 4 (latest build) OS: Windows 10 / Windows 11

Description of the issue: After the recent Razer Synapse 4 update, it has become impossible to remap or disable the top-left side button assigned to "Sensitivity Stage" (Decrease Sensitivity / Sensitivity Clutch).

When attempting to rebind this button to a standard key (e.g., keyboard key "M"), a macro, or even setting it to "Disable", Synapse 4 fails to apply or save the change. The button remains stuck on its default DPI function or completely ignores any user assignment in the UI.

Troubleshooting already performed:

1. Tested on 3 different physical PCs running Synapse 4.

2. Tested with 3 different Razer DeathAdder V2 X HyperSpeed units.

3. Tried logging in as Guest (local profile), creating fresh profiles, and resetting cloud profiles.

4. Cleared Synapse cache folders (%localappdata%\Razer and %appdata%\Razer).

5. The issue affects all tested units and systems exclusively under Synapse 4, confirming a software/driver regression bug in the Button Remapping / Sensitivity Stage module for this mouse model.

Expected behavior: Synapse 4 should allow users to freely rebind or disable the Sensitivity Stage button to any custom keyboard key or macro without UI lockups.

Please pass this report to the Synapse 4 development team for a hotfix.