Since the in-game bug report functionality does not appear to work at the moment, I am instead posting the bug report here. Please let me know in case there's any alternative location I can use to report issues like this and I'll be happy to report this there again.

When switching from the M1 Garand to an attached M7 grenade launcher while having no rifle grenades in the inventory, the animation will play with the player affixing an invisible rifle grenade to the front of the rifle or remove a previously invisible (but now visible) rifle grenade from the barrel when switching to and switching from the grenade launcher, respectively.

From my personal perspective, it might make more sense to play a different (and faster) animation if the player no longer has any rifle grenades in their inventory so as to avoid the issue of invisible rifle grenades altogether.

Steps to reproduce:

  1. Equip an M1 Garand.
  2. Add any rifle grenade upgrade (e.g. M7 Smoke).
  3. Fire the entire inventory of rifle grenades.
  4. Switch back to the M1 Garand.
  5. Notice that suddenly a rifle grenade shows up on the M1's barrel.
  6. Switch back to the rifle grenade upgrade.
  7. Notice that the character affixes an invisible rifle grenade to the M1's barrel.