After updating Jenkins from 1.551 to 1.565.2, our jobs fail, more often than not, with the SVN exception
"E200015: No credential to try. Authentication failed"

I know this has occurred before, but in our case, it keeps occurring, and there are no parameters involved. It doesn't happen every time, but about every second time.

According to the SVN server's connection logs, Jenkins actually tries to connect to the SVN server without giving any credentials in those cases.