I was able to track down some of the old correspondence regarding this issue and it looks like it may be related to something happening during conversion from an older version of CMSB. Fixing this issue will require making some updates to one of the fields in the permalinks table in MySQL, using a tool like phpmyadmin.
If you're comfortable making a change like this, you should just need to update the default value of the "customSourceUrl" field in the permalinks table from "NULL" (the string) to NULL (the value). If you're experiencing the same issue as Jeff this should resolve it.
If you need any assistance making this change or further diagnosing the issue, feel free to send a 2nd level support request using our Support Request form (https://www.interactivetools.com/support/request/) and reference this forum thread.