The monsters go silent. It seem it only loads monster sounds on dungeon level changes. So when you restore a saved game no monster noises until you go down a level. No biggy but thought someone would edit the save game load code to include loading the monster noises by now.

My strategy for playing the game now is turn up the cycles to 15k and use the keypad to move and only save right before going down a level that way I always have monster sounds when playing.

Also as a side note I have the original game and have better scan of the manual and a pdf of the Reference Card.
If GOG wants it they can contact me

Not really sure about this, as I haven't played the GOG version, but maybe someone on the Dungeon Hack sub-forum knows something about this?

Hu? Dungeon Hack is not on GoG!

yeah it is, its part of the forgotten realms archives collection #3

Oh, really?

Yup https://www.gog.com/game/forgotten_realms_the_archives_collection_three

Its a long lasting bug has nothing to do with GOG version. I posted in correct forum Forgotten Reams Collection on this once I found it lol.

Anyways if you use SVN Dosbox you can just use savestates to save/load dosbox games.