I found this in hudson 235 and it is still in hudson 277.

How to recreate it:

• Create project with SVN Repository (http protocol and user/name
  authentication)
• Tick Poll SCM for emaple to '* * * * *'
• After a few minutes change the password of the SVN user you used in
  authentication (Do it in your SVN environment, NOT in hudson - hudson will not
  know anything about password 'expiration')
  Observed results:
  Polling will start endless authentication tries... (about 5-10 requests per
  sec.)
  Expected results:
  After one or two attempts poll should stop trying to authenticate

The problem is in method
SubversionSCM.SVNAuthenticationProviderImpl.requestClientAuthentication(...) {
}
It always returns credentials (invalid), however, it should return it only once
(at the first attempt to authentication). Other words should be aware of input
parameters: SVNErrorMessage errorMessage, SVNAuthentication previousAuth

Witold Delekta