Base64EncodeContext processor causing content repository to grow in size

We encountered this bug causing NiFi content repository to grow in size (and not getting cleaned up properly until a restart) when passing flowfiles with empty content to the  Base64EncodeContext processor. This happens in particular when flowfiles with any content are cleaned (i.e., with a ReplaceText processor) then passed with the empty content to the Base64EncodeContent both in decode or encode modality. We observed this behaviour on NiFi 1.10 both on windows and Ubuntu 18.04, java 8 and 11. Here attached a simple template of a flow to reproduce the bug,
it should generate a few gigabytes of corrupted content repository if run for a couple of minutes.