There's a bug where if an item is not in direct line of sight of the client, the player won't hear the respawn sound effect. It affects both weapons and power-ups.
Example 1:
The player would not hear the Thigh Pads respawn.

Example 2:
The player would not hear the Armor respawn on the box despite being right beside it.


It has been confirmed that this is a base game issue as the respawn effect is spawned and not replicated if a client can't see it.
As a result, the respawn sound also won't play because it's attached to the effect.
Marco proposed a workaround to it would be to give weapons and items a silent ambient sound. This ambient sound could then be replicated through walls within the hearing radius.