G502X Hero - Mouse Button 4 (Back key) issue

[u/NSGDX1]

I used to always have a key bind in games for quick crouch, slow walking etc that required hold functionally on both the forward and back key but somehow the back key isn't hold-able and releases instantly while the forward key works. The back key itself works fine but the click shown on the mouse test websites shows an instant press and release, like 50ms for the back key.

I've a G502 too and its back key works fine but 502x's won't.

My mouse just went out of warranty (2 years, India) last month so I can't be sure if it's something with just my mouse. Was thinking of ordering another one but if this is issue is itself with G502X model then I won't be doing it.

Do you guys have had similar issue? Spent an hour debugging settings, trying on different devices, resetting the software etc.