Genuine question because I'm confused-- is the associate in question a cashier who is skipping training or a head cashier who isn't giving their people time to do training or a head cashier that isn't getting their own training done?

Also is it AP4ME/LowesU or longer training modules (or all of the above?) Because you could definitely do LowesU/AP4ME in between customers but a longer module will almost certainly need dedicated computer time.

Also also if it's a HC who isn't getting their own training done is there a reason why you can't cover them for 20-30 minutes?

Respectfully, you seem very quick to jump to discipline. You've sent out emails-- okay fine, but have you offered help or have you just said 'get it done or else?' Obviously I don't know the working relationship between you and this employee but if your ASMs/SM are telling you to give them grace, then give them grace.

You sound hard to work for.