BIG-IP with /31 self-ips

/31 addresses are typically used for point-to-point links on non-broadcast networks. They only have two possible addresses so a broadcast would be pointless.

From RFC 3021: https://tools.ietf.org/html/rfc3021

In current practice, numbered Internet subnets do not use longer than a 30-bit subnet mask (in most cases), which requires four addresses per link - two host addresses, one all-zeros network, and one all-ones broadcast. This is unfortunate for point-to-point links, since they can only possibly have two identifying endpoints and don't support the notion of broadcast - any packet which is transmitted by one end of a link is always received by the other.

Can you confirm the subnet mask you have configured on your interface as you shouldn't have a broadcast address with a /31 mask. Sounds like you may have configured a mask of 255.255.255.252 and not 255.255.255.254