In the simpler and much older days (
DOS era, Command: Aces of the Deep) you'd get a "prompt" stating:
You can not save now, you are in the middle of a battle - or something similar. So you knew it was a "feature" from the beginning. Of course it was an era were most manuals were read by the players to learn about the game beside their PC and not in the toilet prior to be discarded with the rest of the ... uhmmm solid waste?
comment on game manuals not SH5 specific ... only.