/clone "move" sometimes fails when source and destination overlap

/clone ... replace move should work like /clone ... replace force, and never fail when source and destination overlap. However it does in some cases.

Example that fails:

/clone ~-5 ~-5 ~-5 ~5 ~5 ~5 ~-5 ~-4 ~-5 replace move

Example that succeeds:

/clone ~ ~1 ~ ~ ~3 ~ ~ ~2 ~ replace move 

In both of these cases, the source and destination overlap. However in the first case, the command fails. Both commands should succeed.