A few times a year we get new constituent records from the school, and I use import-o-matic to match these records up, and import all of them. This process has worked great for the last year or two, but after upgrading to the latest version of IOM, I had records merged based on name similarity that was incorrect. I didn't change anything, I'm not aware of anyone else changing anything. What could have changed, and is there something I should check/uncheck to fix this from happening in the future??
In your import profile, under Constituents --> Duplicate Search --> Auto-pick, do you have any auto-pick methods enabled? If the "Score" method is enabled, what value do you have selected in the slider bar at the bottom?