FWIW
The 'standards' are

lame at best, which leave sources attempting to make up for their significant limitations by cramming stuff into the designated fields
No Series???
No Subtitle???
After all these years

Unfortunately, a common subtitle separator is the colon. 90% of the time, that works but what do you do for the other 10% (a reason many things do not let Otto do the job)? And some are just trash (IMHO): 'A Novel', A....