Withdraw w no movement

[TheGrayMouser]

Not sure if this is meant to be but:

I had a heavy Infantry unit in melee w enemy heavy infantry, during the sequence post combat ( ie rout moves etc) an enemy routed unit moved behind the enemy heavy infantry unit ie blocking it from any retrograde moves, then the same enemy HI "withdrew" from combat.... Obviously it didn't move back a full grid which was occupied( and which would have been diagonal) but it actually did disengage from the combat. (I was able to charge it again on my turn w my same heavy infantry.) Logically could make sense as units can coexist adjacently without being in melee, but I have never seen this happen before ( and kinda assumed it was impossible, ie if rear grid blocked then no withdraw from combat.)
Now this was with the Tudor mod but I don't believe any game mechanics files were altered... Just curious is this normal

(this was w P&S Campaigns)

[rbodleyscott]

Not sure if this is meant to be but:

I had a heavy Infantry unit in melee w enemy heavy infantry, during the sequence post combat ( ie rout moves etc) an enemy routed unit moved behind the enemy heavy infantry unit ie blocking it from any retrograde moves, then the same enemy HI "withdrew" from combat.... Obviously it didn't move back a full grid which was occupied( and which would have been diagonal) but it actually did disengage from the combat. (I was able to charge it again on my turn w my same heavy infantry.) Logically could make sense as units can coexist adjacently without being in melee, but I have never seen this happen before ( and kinda assumed it was impossible, ie if rear grid blocked then no withdraw from combat.)
Now this was with the Tudor mod but I don't believe any game mechanics files were altered... Just curious is this normal

(this was w P&S Campaigns)

This is normal. It only happens if a unit routs/pursues into the square after the fall back has been decided on, but before it actually moves. As you say, it isn't illogical because troops in adjacent squares are not necessarily in close combat.