Grinding Vex addendum modified pinions

So we bought some of the vex addendum modified gears specifically the 13T on the 14T spacing for our tough box mini’s to change the ratio slightly. When we first installed them they were grinding so we decided to run them in for a little over a hour. After cleaning gearbox and reinstall everything we tested the gearboxes to see how they were running. When we ran them they made the most deafeningly loud noise. We checked everything to see if it was all installed correctly and it was but still made this super loud sound. it took a lot of force to move turn the output shaft when the motors weren’t powered and it moved like a ratchet when each of the teeth engaged and disengaged on the pinions. So we swapped the pinons back the original 14T pinions that came with the gearbox and everything ran perfectly. We aren’t quite sure why and are wondering if its a manufacturing defect or if we just need to run them in more?

Also when cleaning them the first time the black coating on the pinions had started to be shaved so they were grinding quite a bit.

Did you lubricate them first? What lubricant did you use? How long did you run them in for?

We ran them in for over a hour probably closer to 2 and we tried both the red tacky grease and this white grease from Canadian tire:https://www.canadiantire.ca/en/pdp/motomaster-white-grease-0280806p.html#srp