PGS subtitles behave erratically

[23doors]

Describe the bug
PGS subtitles are seen "catching up" when seeking forward

To Reproduce
Steps to reproduce the behavior:

1. Load movie with PGS subs
2. Wait for some subs to appear
3. Seek forward say +10 minutes

You will see multiple subtitles being briefly shown on screen. Seems it renders all lines between seeks.

Sometimes lines will linger in screen until new line is to be shown.

Expected behavior
Should only render current lines.

[wang-bin]

I need a sample to test