Voice activity analysis (for Auto Sync Subtitles) not working

No. But it’s the location where the various analysis features are storing the decoded audio (in WAV format) before it is handed over to the actual analysation code. If it is not defined in the container, /dev/shm is used instead, which is in RAM and is easily filled up with lots/large files.

Another common source of analysis failing is insufficient memory in the OS kernel’s inode tables: Linux Tips - #9 by ChuckPa
(IIRC in the case of Docker, it’s the kernel of the host OS)