Do you dump out the excess water in the winter? I see these trays don't have ridges. The ones I use for winter do have raised ridges, and even then, the water gets too high and the trees stay too wet if I don't dump it out.
I dont generally get a lot of excess water that accumulates when I am watering them daily. I give them just enough to get the soil thoroughly wet. Any that goes through the pot evaporates usually before the next watering, probably because of the heat the lights generate during the day. I have little square tiles that the pots sit on when in the tray.
When I have gone away for a week, I have taken the tiles out and filled the trays with water so that they are at least 3/4 full and left for a week.
When I come back home, the water is about 1/4 full because the trees have used it and some of it evaporated. The reason I do this is so I don't have to worry about the trees not having water when I am gone for such a long time. I never had any ill effects from this. The trees dont dry out and I have never had them have root issues from it either.
I wouldnt let them stay that way all the time but for a week once in a while, I havent seen any issues from it