Based on the minecraft wiki stating that only using “strict” does not perform block updates, all other modes for clone should perform block updates. If this is the case, this is still a bug for all 1.21.X versions, including the latest 1.21.10-rc1
1.21, maybe 1.21.1 and 1.21.X snapshots as well.
Can confirm for 1.21. Can also add minecraft:tall_seagrass to that list.
This is still an issue?
Also affects b.2.12.17-1.3.7 (I can't seem to choose that from the affects versions list).
Specifically I noticed cloning fences from next to a block to nothing next to it leaves the connector on the side