As you can see in the screenshots attached, moving the copper bulb does not update the comparator power state (a block update fixes this); however, moving the block will properly update the comparator. Unclear if moving the block is actually working properly or just offering a block update nearby to update the comparator.
Linked issues
Attachments
Comments
migrated
[Mod] turbo
That behavior is consistent with any other block you can move and interacts with comparators. Try a composter for example.
See https://bugs.mojang.com/browse/MC-120986 for reference