In some situations cavalry can charge a phalanx frontally and win

I was playing as Makedonia, I attacked a Greek settlement. I had 2 units of Hoplitai Haploi, 2 x 160, deployed properly in a phalanx. They were moving through the streets of the town, because the streets were small they covered the entire width of the street, no enemies would have been able to surround them. Then they get charged by the enemy general's bodyguard (don't know exact numbers anymore, maybe 50 or so). My Hoplitai Haploi were standing still, properly deployed with all spears to the front. The enemy charges the spears frontally. Neither my troops or bodyguards have weapon/armor upgrades or experience. After some waiting, all the 160 hoplitai haploi are slaughtered. The next unit was about to meet the same fate, but then I sent my own bodyguard against theirs and killed them.
How can cavalry charge a phalanx frontally, fight through a very long melee and survive?
I have found from my experience as carthage marching thousands of vanilla sacredband soldiers everywhere that;


When in a town, if you arrange your phalanxe to cover the entire street (Wall to wall) the phalanxe starts being stupid and moving out of formation and barley attacking (I dont know why)

I lost 5 Sacred band to 2 numidian generals before I realised what was happening.

The solution that worked for me is instead of wall to wall make it so the entire phalanxe fits in the road just touching the edges of the road, the enemy generally wont flood around your phalanx and thier instances of stupidity were reduced dramatically for me.

And about them all changing to swords for no reason, this happens when they think the shield wall had been broken, although they are generally wrong and do it too early (im told it used to be better but a patch made the phalanxes stupider, ive only ever played 1.5 though so I dont know), but theres no real way to stop them