I do not see validation related message /stack trace in the previous log. Is validation (table-based) set ?
you may see
"RAR5074 : Table based validation detected invalid connection. Querying the table TABLE-NAME failed. Set resource-adapter log-level to FINE for exception stack trace."
when you restart db & access your app.
[Also, validation will ensure that any new connection received by the application will be valid. In-flight /In-use connections being used by the application during db-restart will anyway fail]
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