2 new growths lost to rot, change pot?

[SundayGardener]

Hello all,

Wondering if I need to move an Encyclia cochleata to a bigger pot after 2 new growths recently rotted at the base and had to be removed.

It's been in SH for 4 months or longer, and was one of the first that I moved. It took the move well, kept producing new roots, and went on to produce multiple spikes of large blooms, and bloomed for a good 2 months.

Could the moisture level in the pot be too high? It has a good-sized root mass. I've tried to capture this in the pictures attached (which aren't great, but the best I could do). There are pictures also of where I think the growths were removed. Yes, there is some lava rock on top with the hydroton, but it is 90% hydroton.

If it isn't the pot and moisture levels, any ideas why this might have happened after 4-5 months in SH? I haven't seen additional rot, but then it might take longer with the more established growths.

In terms of care, it gets flushed 2x week, under T5HO lights and about 20" away from a southern exposure (old house glass). Temps are 68-72 F, maybe higher when the lights are on, but there's a fan. Humidity ~ 45-55. Kelp max 1x month, Inocuor when I have it 1x month.