on java thee is a bug for 18w48a to 18w50a when you have a command block on repeating and always on if that block gets unloaded it stops working when it gets loaded again
Related issues
Comments

on java thee is a bug for 18w48a to 18w50a when you have a command block on repeating and always on if that block gets unloaded it stops working when it gets loaded again
migrated
(Unassigned)
Unconfirmed
Minecraft 18w48a, Minecraft 18w48b, Minecraft 18w49a, Minecraft 18w50a
Retrieved
Sounds like MC-140985