Is there possibly two characters named Iphidamas?
Il 11.218 lists an Iphidamas as son of Antenor who is from Thrace and dies in combat with Agamemnon.
Apollodorus Epitome 1.7.27 lists an Iphidamas as a suitor of Penelope from Dulichium.
Chronologically doesn't work but also the Iphidamas incident in Il 11.218 is an "event" which leads to Hektor's dominance over the Greeks on this particular occasion because it is the narrative Zeus wanted for this part of the battle.

I think these are two different characters and that we should have an Iphidamas_1 and Iphidamas_2