What a shame, Shirley and Calvin
For me this is all to familar, I've had close to a dozen phals do this over the years. At first I thought it might have been the media then the tempts, keeping them to warm & humid. But over time one after another after another ended up with the same gross pattern.
The funny thing is they would lose their leaves, just to grow back - a year later lose the leaves again. Roots were of no issue, all were thick, plump and numerous.
They all would bloom as if they're was no problem - 2x per year in fact.
I've never tested any of these phal for virus. So, can't comment on any of that.
Currently I have 3 phals suffering from the same, both drop the leaves and new growth is beginning at the base of the plant again.
I'm very curious to know what could be wrong with them but at the same time tired of the same ole thing.
I will likey toss them out soon, pots and all.
One thing I have also noticed, none of my phal species suffer from any of this, None!
I have yet to see any spreading from these phals to other orchids, perhaps I've just been lucky