It is what I mentioned here
https://feedback.bistudio.com/T172179#2447268

Notice how you only get a message for B being skipped, but not for C.
C is still loaded, but its dependency cannot be resolved as it was removed afterwards.

That code wasn't built for this. The message is actually wrong as its not a dependency error, but rather a "required addon not found" error.

Its not viable to fix this.
The skip check is done before the dependency ordering.

The C addon loaded in the game first. Saw that B was to-be-loaded, and thus its dependencies are satisfied.
B addon loaded after that, noticed A was missing and removed itself. But C already got through thinking B would be there, and now it's gone.

This will not be fixed. Lets just say chains of skippable addons are not supported.