Closing the loop: this was introduced during the upgrade of internal string library to track Lua 5.2 changes, which makes % replacements illegal unless followed by a digit or %. Unfortunately our own localization script fell prey to this (and seemingly nothing else did?). We’re going to fix the localization script to fix this problem, for now please don’t use % in the product names (note that % followed by a digit never worked correctly, which we’ll be fixing as well).
Sorry about this!