Error Attempting to Purchase Shields

I’m posting this on behalf of an alliance mate who doesn’t frequent the forums much.
During the Army of One event, he attempted, during the final hour of his time slice, to purchase an available 24 hour shield. Unfortunately, the operation wouldn’t complete. Instead, he got a warning that the shield was cooling down.

This is the second time this issue occurred to him - previously in another event.
The shield WAS in fact available, but wouldn’t let him purchase it. Consequently, points and position were lost.

Yes, a CS ticket was already submitted.
Restarting the app didn’t make a difference.
No, the solution isn’t to “avoid using the 24 hour shield” - during a competition, we want to use all the tools available to us.

I’m wondering if anyone else has run into this issue, whether it’s widespread or completely isolated?