Xiaomi Mi Robot Vacuum Cleaner Replacement Side Brush Issues

I bought a Gen 1 Xiaomi Mi Robot Vacuum Cleaner in one of the Ozbargain sales about 6 months ago.
I've also bought the spare brush and filter packs on a couple of the Ozbargain sales since.
I'm having an issue with the side brushes, I've ended up with 4 spares sets (don't ask how), every one of the brushes when fitted don't rotate properly and cause a side brush alert on the vacuum. If I reinstall the original all is fine.
When fitting the new brushes I noted that all of the new ones don't seem to spin freely when the vacuum is off, the new one does.
It seems off that all 8 spare brushes have the same issue. There does seem to be two different types of brushes in the different kits as some of them have round head screws and the rest are flat head like the original.
Anyone else had the same issue?
I've just ordered a kit from Amazon at 20 times the cost ($45), so I'm hoping these are genuine and they actually fit.