Solidworks 2017 SP 4.1

I have an assembly and I have removed a part, everything was fine until my coworker opened the assembly. I realized in my settings I had "treat missing mate references as errors" unchecked and he has his checked (Tools>options> system options>messages/errors/warnings). I looked into the issue and noticed the errors were from the part's MATES (three simple ones) I deleted (part). The mates were grayed out as if suppressed but the option to suppress each mate was available. Why or how can I make Solidworks delete all mates associated with a PARTS I delete from the assembly?

Thanks in advance