ATM SVCs/Signalling

Good morning, I'm working on a project that requires the use of ATM SVCs through a large PNNI cloud. My equipment sits on the edges of the cloud. It appears that static NSAP routes configured on one of the upstream edge switches is being intermittently withdrawn (or blocked). Are there any operators on the list who have experienced this type of problem or could point me in the right direction as to what could cause this to happen? Thank you, -- Mark Borchers Infinite Global Infrastructures, LLC