Fix KozGit#373 from Ionwerks/Doom3Quest@56e6d43. Many thanks to Inowerks

neo/d3xp/Player.cpp

@@ -11052,6 +11052,13 @@ void idPlayer::Move()
 					physicsObj.SetAxis( origPhysAxis ); // make sure motion move doesnt change the axis
 
 					movedRemainder = (newBodyOrigin - movedBodyOrigin);
+					//#373 fix from Ionwerks/Doom3Quest@56e6d43
+					// Defunkt...
+					// NB: Not clear to me what the purpose of leanOffset is, something to do with pushing against walls. The related blanking (to prevent looking through walls)
+					//     doesn't appear to work as far as I can tell. Whatever the intention the vertical component frequently ends up with a stuck offset when traversing stairs.
+					//     Easiest work-around for now would seem to be zeroing any vertical value preserving the intended functionality (whatever it is) in the horizontal only.
+					movedRemainder[2] = 0.00f;
+					// ...Defunkt
 
 					if ( movedRemainder.Length() > commonVr->motionMoveDelta.Length() * 0.25f )
 					{