I might be wrong here too. From an app devs perspective if the key is still existing as an entry, then there must be a means to identify it as deleted. I still feel, it is a limitation where the clarity to differentiate between deleted entries and non-deleted entries could be better. If it is going to be the same way as it is, then from the API side we should not allow empty values to be inserted. Thus, mentioned it as a limitation in case some one tries to delete and still finds the key in the mutable data.
We have limitations to the number of entries in a mutable data and if we don’t clear the keys then it might be a difficult task for a app dev to design and work with. I hope there will be a better solution in the near future which can be debated.
I will read through the posts linked anyways, thanks!