Not sure there’s a way around that, short of programming BPMs to un-engineer your jobs, save the changes, and then re-engineer/re-release (depending original status of the job). Unless you are ok with allow changes to engineered jobs, then you can change that setting in Company Configuration (Modules > Production > Job card).
Other option could be to store these comments in a UD table that stores the Job Num and this comment that you’re trying to save. Of course, that’s not going to be the same as the job header comment field, but you could then also add this field to the JobEntry application.
