Relogging can cause observers to emit pulses

Edit by PHO, updated by [Mod] GoldenHelmet:
Original test world was unreliable because it had the observer looking at lit redstone dust across a chunk border. Test world and description updated to include other blocks on November 2, 2021.

Observers looking at several kinds of blocks emit a pulse on world reloading. The attached test world demonstrates the bug. The following blocks were tested in 1.17.41 Hotfix:

Steps to reproduce:

1. Open the attached world.
2. Close and open it again.
3. See what the dispenser does.

Strangely, the pulse is too short (0 ticks maybe?) for dispensers to trigger so you need a repeater to make the pulse a bit longer.