It's hard for me to lump ExFJ's together with ExTJ's beyond a superficial level. If I have communication problems with one of these types it is usually dependend on whether they are T or F.
ExFJ's are empathetic and tend to be good listeners, which is often not the case for some ExTJ's. On the other hand ExTJ's are pragmatic and don't take things personally, which is not always true for ExFJ's. I think there are different issues here.