HTTP profile stops working intermittently and starts working when we apply http parent profile. Our BIGIP OS version is 13.1.0.3

What do you mean by http profile stops working? Where were you seeing that?

By http profile stops working, I meant, LB stops receiving packets, but when we reapply the http parent profile it starts receiving packets.But, by doing so, LB works only for few hours and again after some time it stops receiving packets. Thean again we reapply the customised http profile and it starts working. This process has been going on for few days.

How did you find that LB stopped receiving packets? What is the error in the browser?

Can you please provide your http profile and Virtual server configuration.

I started the load test from one server towards LB and at the same time, I took the tcpdump on LB and noticed that LB wasn't receiving any packet. However, there was a capture of health monitoring packets.

If there is no packet arrives to the bigip, it is not problem with bigip but with the network. Check routing and vlan assignment across your network.

Or it may happens that you used wrong tcp filter.

The 1st thing you need to be sure, that packets arrives to the bigip.