Web Acceleration module intermittently responds with 0 content length or with resets

We have been fighting an issue with Web Acceleration module for months for one of our 2 applications using it. I’m wondering if anyone else has seen similar issues? We use WAM for 2 different applications each with similar WAM policies but only 1 App has these issues. The frequency of these problems seems to be increasing about every other week or so , what’s happening is they start seeing some requests for content type text/css that is normally served from cache get returned from f5 with Content length 0 using a X-WA-Info of[S10101.C64325.A24931.RA0.U1762392943].[OT/all.OG/includes] The S code says its served from smart cache, the A code maps to the includes leaf node in WAM where our life time is set to honor the servers cache settings, store it in cache for 4 hours and pass those same server cache controls on to the client. Like I said it normally works fine but when this happens we have to clear cache using wa_clear_cache and that usually works but sometimes breaks a different request for content where another wa_clear_cache fixes it for a few weeks.

 

The 2nd issue we see is for some image requests the f5 will send resets and with the reset debug enabled it shows WAM was responsible> Reset cause: BIG-IP: [0x13fa071:289] Internal error ((WAM::SMART) initate_response failed) We have had several open cases with support but they are unable to resolve this. We have seen in traces when the 0 content length issue occurs or the reset issue occurs the f5 is not sending anything to the server but is responding to the client directly from cache. We saw some of these symptoms in version 10 and now on v11.2.0 hf3. Has anyone else seen anything similar with Web Acceleration?