In F5 BIG-IP LTM, AAM, AFM, APM, ASM, Link Controller, PEM, PSM software version 12.0.0 to 12.1.2, 11.6.0 to 11.6.1, 11.4.0 to 11.5.4, when a virtual server uses the standard configuration of HTTP/2 or SPDY profile with Client SSL profile, and the client initiates a number of concurrent streams beyond the advertised limit can cause a disruption of service. Remote client initiating stream beyond the advertised limit can cause a disruption of service. The Traffic Management Microkernel (TMM) data plane is exposed to this issue; the control plane is not exposed.
https://support.f5.com/csp/article/K22541983