Which ROM have you running? The official LOS one? Did you add any packages (gapps, magisk, …)?
For me the locking works fine with /e/ and the official LOS. In fact, I dont understand how it could not work, since:
- secure-boot is disabled -> SBL is not verified
- LOS disables verity mode -> partition hashes are not checked
But obviously I am missing something
Did you check the checksum of the image before you flashed it? Perhaps it was corrupted?
FYI, in the meantime I have built my own LOS version (based on the official version), that:
- is signed with my own keys (instead of the google test keys)
- enables verity mode (disabled in LOS)
- creates a ‘user’ build (instead of ‘userdebug’)
Works like a charm, all with locked boot loader!