Hello, Been seeing this one for the last two versions (pro). Mac running latest version of OS (El Cap 10.11.6)
Properties Panel Title seems to lose render capability at different viewport sizes.
Video: http://forums.tumult.com/uploads/db2156/original/2X/1/1fab45b6ef7562e7c0ef9c3f76b388af565ca1ac.mov
You likely have a custom and/or corrupted version of Helvetica Neue Light installed. You can probably correct for this by going to the /Applications/Font Book.app and choosing ‘File > Restore Standard Fonts…’
/Applications/Font Book.app
I use FontExplorer X Pro and do not see any problems with the noted font. Tested at various sizes with no problems encountered.