Hi, this is an apparent bug in upstream kernel.
I fixed it in my git, please could you verify it works for you? Patch is in this branch: https://git.kernel.org/pub/scm/linux/kernel/git/mbroz/linux.git/log/?h=dm-cryptsetup (and let me know if you want to add reported-and-tested-by tag with your name) Thanks for the report! Milan