ACX platform supports BFD over normal and aggregate interfaces. However, if a BFD session is carried over AE interface and the timer is configured less than 500msec, if there are aggressive statistics pooling or script running to collect data from PFE, the BFD session over AE bundle may flap.
BFD might flap on AE bundle while packet forwarding engine is processing other requests.
On ACX, BFD AE based sessions are as delegated, which is handled by FEB CPU. If there are ongoing queries to the FEB CPU like stats pooling, the processing of periodic BFD packets may be delayed and cause BFD to flap.
For ACX platform, configure 'bfd-liveness-detection' with a minimum timer of 500msec.