The Elder Scrolls: Arena CD version speech playback issues

[SenhorFlibble]

Recently I've installed FreeDOS in 86box, which is configured to emulate a 486DX2 @ 66 MHz, and have successfully run both the floppy version of Arena (1.06) and the CD version (1.07) using JEMMEX parameters suggested here.

The game works fine, but there are issues with speech in cutscenes in the CD version. The lines either cut off abruptly or a screeching noise is heard instead, depending on the sound device configuration. I'm using Sound Blaster 16 (Port 220, IRQ 5, DMA 1, HDMA 5) but have also tried Sound Blaster Pro 2 and Sound Blaster 2.

This error happens every time and in exactly the same places, e. g. in the very first cutscene the speech always cuts off after the words "in this cell" and resumes after the subtitle text switches to the next page. I'm not observing any other problems with sound in the game itself.

I have tried out different options, and among those I copied EMM386.EXE from Caldera DR-DOS 7.03 and loaded it instead of JEMMEX:
DEVICE=C:\DRDOS\EMM386.EXE DPMI=OFF FRAME=AUTO NOVCPI
This did the trick, the speech in the cutscenes now plays fully without any interruption (at least, I tested this with the opening cutscene). Which suggests that the problem somehow lies with JEMMEX.

Is there anything I can do to tweak JEMMEX settings to fix the speech playback? FreeDOS 1.3 comes with JEMM 5.79, but I also tried version 5.83 as well, but this did nothing to remedy the issue.

Arena is a freeware game now, the CD version may be downloaded from GOG:
https://www.gog.com/en/game/the_elder_scrolls_arena

The easiest way to reproduce the bug is to create a random new character and watch the opening cutscene.