I read THIS post at RFO with interest naturally. The thread is about losing dimensions when linked files are updated. A subtle development in the thread is that radial dimension and linear dimensions are affected differently when a link is unloaded. Aaron Maller noticed that, mentioned it (in the thread) and asked someone at Autodesk about it. They looked into it and replied with:
Originally Posted by Autodesk Team
The emphasis was added by Aaron. Okay, good to know. For now, radial dimensions are at great peril if they are referencing a linked project. Best bet is to avoid dimensioning to linked elements anyway but especially so with radial dimensions.