Unexplained intermittent error in OBIEE UAT server only

We made few RPD changes and code was migrated to UAT server. Intermittently, in UAT, we were getting error on report side:

State: HY000. Code: 10058. [NQODBC] [SQL_STATE: HY000] [nQSError: 10058] A general error has occurred. [nQSError: 27005] Unresolved column: "Dim - Derivative"."Derivative ID". (HY000)

As a work around, we would clear the cache, delete cookies, close browser completely and try again. This time error was gone. The error kept coming back next day, and we could also recreate the issue just be repeating steps for work around.

I asked admin team to look at it, and we found that this was happening due to clustered environment in UAT. Probably one of the server was still pointing to old RPD.