White subtitles appear grey in HDR movies

[Kihikihi]

I’m seeing an issue where white subtitles appear grey in movies with certain HDR content.
First of all, here are my subtitle settings:

And here are two different versions of Lawrence of Arabia, the first one is a HDR10 version:

Next up is a Dolby Vision version. The colours are fine but the subtitles appear in a washed-out grey colour (not easy to see in this screenshot):

What is causing this to happen? A problem with the tonemapping?
FYI I did try and override subtitle fonts and styles in the settings, but that didn’t change things.

On a non-OSMC Kodi build, I don’t see this issue.

[darwindesign]

This was covered pretty recently in the following thread…

Subtitle color only in gray

Hello, my subtitles are always displayed in gray. Changing to another color is unsuccessful. What is the problem?

[Kihikihi]

This was covered pretty recently in the following thread…

Thank you! I just bought a Vero V, it seems like that might fix the problem…

[Kontrarian]

I have this DV disc and the subtitles as seen in your first picture are the SDH subtitles and the second picture is the standard subtitles.
This is from my remux with PGS subtitles.
Not sure what your two sources are or if their subs are PGS or SRT but I’m almost 100% certain that your first picture is SRT since the second line is part way out of the frame and I’ve never seen PGS subs do that and your second picture appears to be PGS subs since it matches perfectly with mine as far as font and placement.

PGS subs can not be changed by Kodi settings.

[Kihikihi]

You’re right @Kontrarian, that first shot was of the SDH subtitles, and they were indeed SRT. The second remux uses PGS subs. I didn’t realise Kodi can’t control their colour. Thanks for posting your stills!