Forum Discussion
1.For many entries in data groups better use external data group:
https://support.f5.com/csp/article/K73862425
2.Another thing is to enable logging at different level to see if you requests match the irule at different stages:
https://support.f5.com/csp/article/K55131641
https://devcentral.f5.com/s/articles/the101-irules-101-logging-amp-comments
3.Also as note with your version you can try to use F5 Local Traffic policies as they support data groups and are less buggy or CPU intensive than iRules:
https://techdocs.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/big-ip-local-traffic-management-getting-started-with-policies-14-0-0/01.html
4.The final thing is to look the bug tracker if you checked everything like the irule matching the traffic, etc. You searc by "data group" and see if you match a bug:
https://support.f5.com/csp/bug-tracker?sf189923893=1