Intermittent object failure in one of the nodes

1) 3 Node RAC 11.2.0.2 clusterware, database software version 11.2.0.2

2) Active dataguard configuration runs on same 3 nodes. 3 instance primary, 3 instance active dataguard (open for queries in readonly mode for online customers 24*7). 3) "PLS-00801: internal error [hshuid:LU invalid]" occurs on active dataguard readonly database on one of the instances, the same pl/sql unit runs fine on other instances of active dataguard. 4) The error occurs at RUNTIME not at COMPILE time on only one of the instance of active dataguard, the other two instances are running the same unit fine. (All Oracle notes on support website talk about same error at compile time). 5) The pl/sql unit runs