I just checked on my install (made using git and compiled/installed locally) and everything works fine. Seems like it's either something from the pre-compiled Windows version or a mistake while installing.
Well, I don't know what I'm doing wrong, then. Tried a brand new install and still have the error. The following is the exact install procedure I've used in Windows 7:
a) Redownload latest nightly: openxcom_git_master_2015_07_13_1222.zip
b) Redownload latest Commendations: 2015_05_25 Nightly.zip
1) Create d:\Games\OXC folder
2) Copy contents of openxcom_git_master_2015_07_13_1222.zip to d:\Games\OXC
3) Copy original UFO files to d:\Games\OXC\UFO folder
4) Copy contents of universal_patch.zip file to d:\Games\OXC\UFO folder, overwrite all files
5) \User\Documents\Openxcom folder is completely empty
6) Test game, everything works including MOD description text
7) The following is automatically added to \User\Documents\Openxcom foder: mods folder, options.cfg and openxcom.log
8) Copy Commendations contents from 2015-05-25 Nightly.zip to d:\Games\OXC folder, overwrite all files
9) Run game, get STR_MODS_TOOLTIP instead of mod descriptions
10) Enable Commendations mod in mod list
11) OXC reloads STR_MODS_TOOLTIP is still there instead of mod descriptions.
So, what am I doing wrong? Everything seems to work except that one string, but it doesn't make sense to me why that one string is wrong. And, if that is wrong, it makes me wonder what else might be wrong that I can't see right now.