PI interface for OPC DA - CPU to 100%

We are migrating OPCDA to a new machine and observed this weird behavior. Initially, we migrated with version 2.7.2.20 and now with 2.6.15.13 same issue. We have around 80 interface instances to migrate. At around 15 instances the CPU shoots up to 100%.

 

We are using the interface in WARM failover mode. I tested this without failover and things work fine. Most probably i have isolated the issue being failover. Do anyone know how to fix this ?