I was about to ask this, but found it answered already on the polish FAQ.
Does the FAQ team agree with this point of the polish FAQ?
61. Morale tests are made at the end of activation of unit that caused them. What happens if a unit takes loses from Wait?
In such case the morale test is made at the end of activation during which the loses were caused. Let's say that during activation of unit X unit A killed enough models from unit B to force it to make a morale test. At the end of activation of unit X, B has to take this test (note, that B and X may be the same unit).