fvdemount with multiple sources does not work properly

[dnozay]

Situation: 2 FireVault partitions on a 4TB disk that I want to mount concurrently

# fdisk -l /dev/sdb
GPT PMBR size mismatch (4294967294 != 7814037166) will be corrected by write.
Disk /dev/sdb: 3.64 TiB, 4000787029504 bytes, 7814037167 sectors
Disk model: BUP BK          
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

Device          Start        End    Sectors  Size Type
/dev/sdb1          40     409639     409600  200M EFI System
/dev/sdb2      409640 3907380119 3906970480  1.8T Apple Core storage
/dev/sdb3  3907380120 3907642263     262144  128M Apple boot
/dev/sdb4  3907642264 7813774983 3906132720  1.8T Apple Core storage
/dev/sdb5  7813774984 7814037127     262144  128M Apple boot

hence I provide 2 sources:

# fvdemount  /dev/sdb2 /dev/sdb4 /mnt/fvdevolume
fvdemount 20240502

Logical volume: 1 is locked and a password is needed to unlock it.

Password: 

however only one of them gets mounted.

# ls /mnt/fvdevolume/
fvde1
# mount | grep fvde
/dev/fuse on /mnt/fvdevolume type fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0)

It would be nice if you could also mount different sources sequentially, but second call fails.

# fvdemount  /dev/sdb2 /mnt/fvdevolume
# fvdemount  /dev/sdb4 /mnt/fvdevolume
fuse: mountpoint is not empty
fuse: if you are sure this is safe, use the 'nonempty' mount option
Unable to create fuse channel.

Thank you