Panning issue with SWAV samples

[SombrAbsol]

For example, in Mario Kart DS, there are two car samples that can be played when the game starts: a double "vroom" or a long "vroooom". In the case of the long one, a panning effect is supposed to be heard, moving from right to left. However, VG Music Studio doesn't produce any sound at all.

This is normally the expected result (recorded via DeSmuME from an MKDS ROM whose SDAT file I modified, so there is no Mario's "Here We Go!" or "Yahoo!" sample).

And this is a screenshot from Nitro Studio 2, with the command that I think is causing the issue:

Removing it makes the sample playable in VG Music Studio, but the panning effect is lost; here, removing the notewait_off command will only take pan 124 into account for panning.