Hi Michael,
Thanks for your reply.
The iRule I made was just for testing and it's matching a single IP (10.1.0.2), what about if I have different clients with different IPs. It's ok for multiple client's sharing the same IP but they should stick to that IP during the session.
Unfortunately, I'm not aware of the application capabilities, but the team will come back again for the DR testing and it's a good idea you are providing here which could be a solution if next test confirm that SNAT pool causing the issue.
Thanks a lot all for the great support, I will get back and post the test result once done.
BR,
Abdul