@flattery6159,
Thanks for reaching out.
Admittedly I do not have a ton of experience with threading and/or this particular flag but I’m assuming it is specifying the number of threads used when decoding video content. AFAIK, the value set here should correspond with the number of cores your machine is using.
I do not think there is any risk to you here. I would recommend trying to disable Hardware Acceleration instead of using this command line flag though to see if it resolves the issue (Settings --> System --> Hardware Acceleration).