Subtitle adjusting not working

Hotkeys for subtitle adjusting not working. Tried to change the keys to other but didn't help. There is no double bind so that is not the problem. Is this bug or something that can be fixed by me?

Version 15.0.9 Mega, also tried updating to beta 15.0.10 Mega.

Are you talking about the subtitle delay?

That only works when using the internal subtitle renderer.
MPC-HC options > Playback > Output

Yes. This solved my problem. I set DirectShow Video to madVR to get subtitle renderer setting available. Now its set to Internal Subtitle Renderer and adjusting can be done. Don't know what was the right pick for DirectShow Video but madVR seems to be working OK with quick review.

madVR is fine.

Normally the default is set to "Enhanced Video Renderer (Custom Presenter)", which is also compatible.