Missing HTTP response headers from BigIp LTM

I have an nginx webserver sitting behind a BigIP LTM. The nginx server receives long-poll HTTP requests from clients and return a response that contains caching headers (Etag/Last-Modified) that are used for the proper functioning of the long-poll system. The problem that I'm facing is that long poll requests to a virtual server with a public IP do not have the 2 headers in the response. The headers are in the first response but subsequently do not get included. The "date" response header is also incorrect as it's several hours earlier than what I'm expecting.

 

 

I also tested by making the requests to the internal IP assigned to the nginx server and the headers do get included in each response as expected. So I'm thinking the virtual server configuration has something to do with it but I'm not sure where the fault lies.

 

 

Edit: I've reposted in the "New to F5" forum instead, please disregard this post.