This has been reported multiple times but there hasn't been a solid response from the Crysis team (from what I could tell). So yes, I know this is not completely unheard of, but I'm just thinking of 'refreshing' the bug so the dev team is aware of it.

Essentially, this issue arises by, firstly, collecting some Nanosuit Upgrade Kits from certain areas. Then, you unlock any of the Nanosuit Modules (in my case, I chose to unlock the 'Extended Cloak' module). You'd equip it and then continue playing. At some point during gameplay (people say during Cutscenes), the said Module you unlocked becomes re-locked and you CAN NOT go back and re-collect the Nanosuit Upgrade Kits.

This specifically occurred for me when I was playing the beginning of Red Star Rising. After I collected the second Nanosuit Upgrade Kit (This one: http://oyster.ignimgs.com/mediawiki/apis.ign.com/crysis-3/3/38/Mission5_17.bmp), I opened up my Nanosuit Module Menu and saw that Extended Cloak was re-locked.

If it helps, I'm playing on a PS3 system. However, from what I've heard, this issue is present on all consoles.

This is a prior thread created on the issue: http://www.gamesas.com/forums/viewtopic.php?p=607733#p607733