ActionTextRichTextRecordSet now calls check_associations_dont_exist to
ensure imported ActionText records only reference records within the
same import, matching the behavior of the parent RecordSet class.
ZipKit creates a placeholder record when add_file is called, this record is then filled with the content that's passxed to write. But if the blob's file doesn't exist then an error is rased and the placeholder is never filled. This results in a ZIP that has a place in its catalog for the blob, but no contant for it, which makes it invalid.
Without this exporting, deleting and then re-imporing an account would reuse the old cache entries since the IDs are the same, but those cache entries will likely have the old account ID and would break
Stanko K.R.