Z9x Pro - Subtitles cause black boxes and lose their outline when screen is bright

I have been enjoying the smooth playback on the Z9x Pro but I've noticed a rather annoying issue with PGS subtitles.

It seems they are causing dark boxes to appear when the screen gets too bright, from my perspective its as if the Zidoo Player is trying to compensate for the bright screen and creating darker boxes for the subtitles to stand out. This is very distracting and I'm not quite sure how to fix this.

I have tried using ZDMC instead and the issue is not there. Running the file locally on my PC and the subtitles appear as expected. This only happens when using the Zidoo player.
ZDMC 20.2 has really choppy playback and I can't get it to work reliably so I don't want to go this route.

I can even move the dark box with the PGS subtitle settings. Everything points to the way the Z9x handles the PGS subtitles but I'm not sure what settings I can tweek to resolve this.

I'm on the latest firmware release 1.0.52

 

I've been going through testing and this seems to happen if there are two places the subtitles need to appear on. For example if the subtitles are at the top and the bottom of the screen, the subtitles will show improperly.

 

Doesn't seem like this product is very robust. I also get crashes while subtitles are turned on. Always at the same time, issue resolved with subtitles off.

If this thing could support subtitles it'd be my daily driver, but until this product stops crashing and that subtitles display properly, I really can't recommend it.