Jira integration database connection issue

After upgrading to 1.3.1, thousands of lines of the following error are logged daily in our confluence which uses Jira for accounts:

2004-12-29 09:49:08,103 FATAL [user.providers.jira.JiraJdbcProfileProvider] Unable to close connection: Connection is closed.

The database used is MySQL 4.1 and the DB URL has the ?autoReconnect=true so the connections in the pool should remain open until explicitly closed.

Confluence starts to log the rows pretty much immediately following a restart so I suspect there's something funky in the startup process which leaves a broken connection into the pool.