ASM is not supported on connection-mirrored virtual servers.

You can't enable connection mirroring on ASM and generally speaking connection mirroring is not needed for HTTP connections.

This is because unlike other protocols (like SSH for example) in HTTP one TCP connection does not equal "one user session".

See knowledgebase article "K8637: BIG-IP ASM-enabled virtual servers do not support connection mirroring":

https://support.f5.com/csp/article/K8637