It comes down the definition of both “Incidental contact” and “Affect the play”:
Incidental contact: Any contact which is not dangerous in nature and does not affect the play.
Affect the play: A breach affects the play if the outcome of the specific play may have been meaningfully different had the breach not occurred.
So if
– a player makes an attempt to block/takes a catch, and
– contact occurs during that attempt (remembering that the whole action is considered as ‘during the attempt’, which includes what happens after they contact the disc), and
– they would not have been able to make the block/take the catch WITHOUT initiating that contact
Then this is NOT incidental contact and constitutes a defensive/offensive receiving foul.