I'm currently have the same issue with a number of browser based forms created in IP2013, having disabled the Enhanced Rich text option on the control. Users are advising that when they input data there a multiple blank lines appearing after the content. Upon inspection of the .xml file I can see numerous <"br"><"/br"> tags (without "s) after the main body of content.
We have also recently seen a postback error logged in Event Viewer, related to this issue.
Does anyone know a possible solution, other than removing all Rich Text controls and changing them all to standard multi-line text boxes?