[hotstud]

If a song is left running it continues to use the same instrument mod that was equipped when the pulse finished regardless of changing equipment. For example you could start Selos with a drum and then equip weapons instead and it will continue to have drum speed until you stop and restart the song.

Also I just checked and this appears to only happen with a higher instrument mod starting. If I have weapons equipped and I start selos I can equip a drum and I'll run faster on next pulse without restarting song. I can then equip weapons again and it will slow me down on next pulse without restarting.

It's only if you switch to a lower mod after starting the song that it doesn't update.