Patch coming. Spun off from #1901456: META: Config syncing does not work reliably.
This includes the patch from #1889854: Config import breaks on protected entity properties, I'll reroll once that's in.
Since this directly affects all blocks, not just creatively named other entities, bumping to major.
A central problem space here is that you're making the assumption that everything after the config prefix belongs to the ID.
So far, I never wanted to make that assumption — because it will inherently prevent us from horizontally extending config entity objects; i.e., like this:
mymodule.type.foo « Only this is the entity config.
mymodule.type.foo.othermodule « Essentially this.
In essence, this issue + patch duplicates #1831774: Config import assumes that 'config_prefix' contains one dot only
Let's not duplicate that discussion.
I think #2 is a waste, and I can't even comprehend how you propose to make that work.
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