Slitherine

The situation was the following :

A group of LH, being charged by medium foot , fled and did burst trough an infantry unit ( dirputing them ) . But the 2 last rank of the LH did not reach the infantry unit, so the firts rank was putted on one side of the infantry and the 2 last ranks in front of the friendly infantry unit . The pursuing medium foot catch the LH but fail to break them after impact and during melee. The LH may not break off as the medium foot is disrupted .

So what happens with the LH unit . It is "divided" in two by the friendly infantry . How does ii conform . Does the rank that passed through the INF come back and push the attacker a bit back to make room or is the friendly INF pushed back to make room for the LH to be happily reunited ...of course afterwards it might mean another burst trough by the LH unit if it looses melee

This is from memory...
In a legitimate interpenetration the BG is split. In a burst through the whole BG goes through even if only one base reaches.
I would suggest in your situation, the conforming moves the other BG out of the way if possible. I've never seen this one happen.

LH can only legitimately pass through LF, so if it was not LF it bursts through the foot, ending completely on the other side, if possible. If this is not possible the evader is destroyed.
If the LH was passing through LF, it will be split as you did. The LH are disordered as long as they are split. When the enemy foot contacts them, the contacted bases must turn to fight them, dropping to disrupted. The charging BG conforms to the LH. In the maneuver phase the LH BG could reform to face the enemy BG but would still be partially interpenetrating the LF and would remain split until the LF were able to move away or the combat with the enemy BG was concluded with one or the other BG breaking.

Thanks

I was so tired that day that I missed the fact that in a burst trough, they would have passed through the all way long