Riley says that she realized she had feelings for MacGyver since they were in Germany, Psy-Op + Cell + Merchant + Birds (2020). She was still in a relationship at that time. It wasn't until almost six months later in Windmill + Acetone + Celluloid + Firing Pin (2020) that she started to show interest.
The homemade diamond Mac pulls from his equipment is already cut and polished for the ring. Even if he could make diamonds in his kitchen (big if), it would be a glassy nugget, just like a natural diamond.
The IP address they discover is in standard IP4 format, but the address cannot work since the highest any number between dots is 255 and the address they find is 257.68.695.84. Two of those numbers cannot work.