Question for if you leave before meal

So at my store they require us to put in an hour of ppto to cover our meal if we leave before it. Is this standard fair across all Walmarts, and if so can someone explain it?

This is the first time I've worked somewhere you have to pay for your unpaid lunch if you leave before you take it. I asked my store manager and other leads and no one seems to know or can explain it to where it makes sense.

I once reported it and was told I would have someone meet with me and they never did. I just feel it's a way to get them to burn your already limited ppto.