When renaming a sharded collection, each participant shard is executing some code aimed at copying existing range deletion documents from the source namespace to the target namespace. Subsequently, this code is executed to delete range deletion documents referring the old namespace.
The range deleter service observer is reacting by deregistering the range deletion task for each deleted document: since renaming preserves collection UUIDs, this results in wrongly deregistering range deletion tasks belonging to the target collection.
As the new range deleter service lands in v6.2, the release candidate is the only version affected at the time of writing this ticket.