It's actually quite serious: they accused the 89C55WD of being a faulty part, wheareas the indications are that it was doing exactly what it says on the tin!

This is how rumours start; eg, "don't use the 89C55WD - I saw a thread once saying the MOVC doesn't work properly"

So - come on guys: is there a real problem here, or not?
You need to either post futher evidence of a problem, or post a conclusion that there is no problem.