My Mtssa. Dark Star 'Orchids Works" is sooooo overgrown in a 4 inch pot that many of the new pseudobulbs are coming in with pleated leaves. I haven't been able to repot because it had so many spikes; many have opened but several more have emerged and are still in tight bud. I placed its pot inside an 8 inch pot and tucked sphagnum beneath the pseusobulbs hanging over the edge of the 4 inch pot. I hope this helps provide some more moisture to them.
It seems counter-intuitive to have an oncidium in semi-HP with pleated leaves but I guess the problem is no different than mine.
I hope this works for both of us
orchidbingo