In the LIghtroom 4 Export menu, when exporting a video file, the extension in the File Naming Example doesn't get updated when the Video Format is changed. For photos, this happens immediately. For videos, it doesn't happen until the Export menu is closed (by clicking either Plug-in Manager, Cancel, or Export) and then re-opened.
Bec Sowada • Adobe Employee, May 31, 2012May 31, 2012
This bug has been fixed in the Lightroom 4.1 release, available now. To get Lightroom 4.1, go to the Help menu in Lightroom and select Check for Updates, then follow the prompts. Or, you can download Lightroom 4.1 from adobe.com.