Doesn't have to be a mis-click to contain no malice.
There is something to be said for sheer absent-mindedness too. In this is the cause, then in this instance, it has undoubetly cost you equity. For the most part though, seemingly illogical moves like this will make you bucket loads of spundoolicks.

I used to instantly conclude these types of incidents
had to be collusion, but have since mellowed.
If on a Crypto or Stars, then dodgy site Sharkscope (which I neither use, nor endorse) will allow you to search for the players results.
They allow subscribed members to search for players results when together.
It lets you see if they play the majority of their sit n gos together, this usually is a bad sign. It also lets you compare their ROI when they play together, along with their ROI when they play alone. A significant increase in the former would strongly suggest collusion.
A mostly pointless affair though, because the sites themselves have software that automatically detects such things. Believe it or not, they actually do care about catching the cheats.