Hi, my hope is that the plant is an old Laelianthe... But let's wait and see. The flat new growths look like Laelia anceps, but the large bifoliate adult growth reminds of a Guarianthe. I'll post photos if it blooms.
As long as we're making wild guesses, one can get that unifoliate/bifoliate combination with L. anceps and C. intermedia... Lc. Interceps or something related. Well, we will see.