Direct play animes with heavy subtitle usage dropping frames. (Karaoke)

[Mkilbride 87]

For example I am watching the Apothecary Dairies right now, but I've had this in a lot of other anime. When lots of subtitles are being displayed on screen, or say a Karoke'd opening like it has, it will noticeably drop frames to become almost a slide show, but the episode will play fine. If I burn in / transcode the subtitles it seems to be fine, but that's quite annoying to need to do.