Phantom/ghost car calls randomly latching. Kone.

I have a kone monospace that randomly latches car calls by its self. 6.7.18 A software. I have replaced the button ribbon cable but to no avail. I was thinking of swapping the mul board next but I was hoping someone may have seen this before and may have some ideas? It can happen in all positions in the shaft and it happens quite often, every 5 minutes or so it will put a random call on, usually it's either buttons 4,3 or 2 (it's a 6 floor elevator). I have also swapped the buttons with new ones (one at a time).
Cheers

Lce operating system right? If it is with the new EN 81-20 standard and the light curtain fails, it may well do this. If can't close the door, it will try to make a call to another floor.
If you take a button to a floor, does it still drive there?

Yes lce and EN 81-20. It will phantom call whilst the elevator is in motion and when it is stopped at floor Level. That would eliminate the light curtain right.

Check for corrosion