We are running istio 1.5, deployed through helm chart on EKS. For one of the service, we are getting consistently 503 with UC response flag, when we include a parameter in URL query string.
The parameter in the query string is to get number of results from backend, its something like ?$top=30, if we have the number as <36, we get proper result, but anything above it gives 503.
Noticed that, when it throws 503, I am seeing multiple calls for same service with in milliseconds difference in proxy logs.
We ran same service on Istio 1.2.2 version, and we dont see this behaviour there.
Appreciate any help or pointers to trouble shoot this issue.