YouTube SRV3 subtitles reportedly being disabled, users report custom captions no longer working
piunikaweb.com
YouTube appears to be cracking down on SRV3 subtitle files, disabling new uploads and deleting existing custom captions from major channels including Hololive, Dream.

These offer customization like colors, text styling and positioning and are used to distinguish who is speaking or for karaoke subs and are now potentially being lost forever.