(Not an MG team) i had a retreating squad, and one member got stuck on a pebble, but the other squad members kept running, then, after two seconds, they ran BACK to the location where the other guy was stuck and only continued back to the back once he got unstuck.
I like to refer to retreat as a broken feature. It is supposed to preserve your squad by giving up your position to the enemy. It does not seem to be working as intended these days, and is often bugged, and doesnt work. (Squads getting suppressed on retreat, retreat getting cancelled because Joe/Hans/Ivan like to rebel against High Command and rather get themselves killed)
They decided to help get his foot out of the pebble.
I agree that the feature is very buggy and really needs to be looked at. It can get annoying(exciting for me) to lose squads just because of one silly thing like you mentioned.