A disimprovement was made in 7.1 that brought null values to Web Content Templates and Structures that were created in 7.0. This can crash web content templates when a user tries to select these blank options and the template logic isn't setup to handle null values.
The issue may not have been problematic in Velocity but it can be catastrophic for Freemarker when developers haven't used an attempt and recover block.
1) Create a web content template and structure that includes a select with three options
2) Try adding content to that structure and notice there is a blank entry at the top
No Blank Entry
Workaround for those template developers reading ... In an admin theme do this to avoid having to write an override.