Symantec GTM has this configuration. 2 pools are configured separately with primary DC VS and secondary DC VS. at WIP level primary DC VS is selected as primary pool and secondary as last resort. manual resume is enabled in primary pool per client requirement. if you can disable it at pool level for permanently, pool will come up automatically and GTM will return primary DC IP. Or you have to enable it manually.
Didn't why this could be the reason for sev1, when everyone knows option of manually enabling pool in GTM??