Depth pass conversion error

[Seyon Sivarajah]

Circuit:
Circuit(3).H(0).CX(1,0).H(0).CX(0,2).H(0).CX(1,2)

test_depth_hyp

after pass it just contains a single hadamard

The same circuit appears to work correctly in pure tket2 rust so there is probably some error in the conversions.