In reality, any test other than the earth continuity is pretty pointless for appliances like washing machines.
Even the IR test, to a certain extent.
So many circuits and parts get switched in and out during the washing machine's cycle (pumps, heaters, drum motor, etc.), you're never going to catch them all, unless your test sequence duration is the same as the wash cycle duration!
Added to that, you may get decreased resistance/increased leakage from things like damp ceramics in the heating element.
If it were an appliance such as a cooker, the standard advice would be to turn the cooker on, and leave it to heat up for a while before perfoming the electrical tests, so the moisture can be driven out.
This is obviously not an option with a washing machine.
Certainly speak to the manufacturers, but you may well be on a hiding to nothing here.
C&G 2377 -01 & -02