Deep Red has multiple cuts. The YTS 720p BluRay is typically the 126-minute Director's Cut . If you use subtitles intended for the 105-minute International version, they will fall out of sync significantly as the movie progresses.
The subtitle file for the release by YTS is generally considered functional and synced for that specific 720p BluRay encode. However, the quality of your viewing experience depends heavily on which version of the film the subtitles are designed for—the original Italian "Director's Cut" or the shorter English "International Cut." Key Subtitle Considerations for Deep Red subtitle Deep.Red.1975.720p.BluRay.x264-[YTS.AM]
Look for the specific "YTS" or "YIFY" tag on Subscene to ensure the frame rate and timing match your file. Deep Red has multiple cuts