Vending machines under maintenance

I’ve always wanted to check out the Pokemon vending machines, but have never been able to because I don’t have any near me.

I’m a freelance contractor, and today I had a job in an area that had two machines within 10 minutes of each other, so I was super excited to get done work and check them out, even though I knew they would probably be sold out.

Both of the machines I went to were “under maintenance”, and it was super disappointing.

I could understand one, but does anyone know why BOTH machines in completely different stores would be under maintenance? Does this always happen?