These seem to be 2 different things.
1) (Batch) deleting entries from collections
I was not able to reproduce this on the latest next
branch.
I tried creating and deleting entries using the batch functionality, querying the api inbetween but it always showed the correct entries. Never deleted ones.
@chechoribero do you have a sure set of steps to re-create the issue? How many entries does your collection have? How many did you delete?
Did you test if refreshing the cache solves the issue? (still, this would be no solution, only an indicator in which direction a fix might be needed)
2) Deleting singletons
When a singleton is deleted, there is actually nothing deleted from the DB but only the singleton spec file is deleted
So if a new singleton is created with the same name and fields the old data entries will still be there. Deleting the cache does not change anything about that.
This is not ideal and I pushed a PR for that - so this might be fixed in the future.