That’s unusual, as the mix setting on my Panasonic industrial S-VHS decks blended them across both channels. Came in really handy for a couple projects, as I couldn’t really do any fancy audio mixing back in the 90’s.

It’s maddening how many video labels didn’t bother with proper labeling on the audio. Only a couple studios like Universal even bothered to mention the linear audio using Dolby noise reduction once Hi-Fi was standard.

I would be willing to take a shot at a beta transfer if you want to buy a copy and send me the tape.
https://www.ebay.com/itm/THE-TERMINATOR-Schwarzenegger-on-BETAMAX-Tape-BETA-NOT-VHS/163313673890
Due to work being done on my house, it will be a few weeks before I can hook my betamax back up though.