When a beacon is deactivated due to losing sky access, it does not play the beacon deactivation noise. When you remove the obstruction and activate the beacon again, it also does not play the beacon activation noise.

To reproduce:

1. Create a beacon and the multiblock pyramid beneath (NOTE: The beacon does not need to be at full power for this bug to occur).
2. Wait for the beacon to activate
3. Place a block over the beacon and note that while it deactivates, the beacon does not play the deactivation noise.
4. Remove the block and note that while the beacon reactivates, the reactivation noise is not present.

This bug is present in both 1.15.2 and 20w20b.