Not everyone can see everyone's dice

All of us have everybody enabled for dice rolls, but one person only shows for the DM and not on screen or in the game log. Very hard to know what is happening. They do have everyone chosen to see.

It sounds cliche, but have they tried flipping the "to everyone" setting off and then on again? Not the one on the character sheet; the one on the Maps VTT screen. This has been effective when this has happened for people in my campaigns.

Are they in the same CAMPAIGN on D&D Beyond? Because that's required. The fact that you're not seeing in the Campaign Combat log tells me they're probably not in the CAMPAIGN ...