Update failure E000022 after upgrade to subversion 1.9.6

[duglas]

Hi,

After upgrading to subversion 1.9.6
My latest svn update attempts result in the following.

svn update /usr/ports
Updating 'ports':
svn: E000022: Error converting entry in directory '/usr/ports' to UTF-8
svn: E000022: Can't convert string from native encoding to 'UTF-8':
svn: E000022: ?\A89'

Coincidentally it also occurs when attempting to update /usr/src and 
/usr/docs as well.

Attempts to portdowngrade to the 1.9.5 version fail similarly.

portdowngrade devel/subversion r435830
svn: E000022: Error converting entry in directory 
'/usr/ports/devel/subversion/subversion' to UTF-8
svn: E000022: Can't convert string from native encoding to 'UTF-8':
svn: E000022: ?\A89'
Something went wrong with svn...  Ensure you have the correct revision!

Any pointers appreciated.

Cheers