Why does Plex take so long to load a movie?

I’ve had this issue with Plex since day 1 where if I load a movie it takes about 10 seconds to load and same thing if I skip to a chapter.
I’ve used VLC too to make sure that it wasn’t my client or NAS that was causing this issue and was able to confirm it as VLC was able to load things instantly as well as skipping to any chapters.
Is there any upcoming update to fix this or is that behaviour normal?