NEC 60xM5 screens

Hello,
I work for the US governement in stuttgart Germany building conference rooms for EUCOM customers.
We installed these screens (see subject) at a customer site less than a year ago. They have called us on site twice in the last two months becasue the pictures on the screens appeared pink to them. Unfortunately, when we arrived on site and powered the screens up, they were not pink. We cannot seem to mimic the pink tones to troubleshoot the issue and the customer has not been able to call us to come up when they are pink. They want us to RMA the screens but we cannot do so until we are able to troubleshoot the problem and/or identify the problem.
Please send me some troubleshooting ideas so that we can proceed with providing some satisfaction to our customer.

Thank you,

Heather M Benton
SAIC/TSIO-E
Deputy Program Manager
Office +49 711 680 6552
heather.benton@us.army.mil