Scheduled ticks get lost when leaving chunks (Redstone components get stuck)

After unloading and reloading a chunk with various active redstone components by flying away, the redstone components are stuck.

This is likely caused by scheduled ticks not being saved correctly for some reason.
Note that the components keep working if instead of unloading them by flying you leave the world and enter it again.

Steps to reproduce:
(0. Make sure you are not in the spawn chunks)
1. Build a repeater clock
2. Fly far way (render distance 2 helps)
3. Come back, see repeaters stuck

Video: https://youtu.be/S48ctDkQw3Y

Affected components:

• Command blocks (Kind of important, because this hinders testing for issues regarding chunk loading)
• Repeaters
• Comparators
• Redstone Torches
• Redstone Lamps
• Observers
• Falling blocks
• Buttons
• Pressure plates
• Tripwire hooks
• Scaffolding
• Chorus Plants
• Water/Lava
• Detector Rails