/vendor is now using erofs in these ROMs. The developer of the TWRP you're using does not include that, so it can't mount.Tried to install this using TWRP, and it gave me "Failed to mount" errors at the end
Code:script succeeded: result was [1.000000] Updating partition details... Failed to mount '/system_root' (Invalid argument) Failed to mount '/vendor' (Invalid argument) ... done
TWRP also warned on reboot that no OS is installed - but it rebooted into crDroid successfully! Are those errors something to worry about?
It doesn't matter unless you want to modify files in it.