As per the title, I have the necessary rank in science (and gun nut) perks to create certain weapon mods, and I have all of the necessary materials, but the "build" button is not highlighted and I get the message that I do not meet the requirements to make whatever the thing is.

Have tried restarting and advancing another level to see if the problem was that mods were mistakenly tagged as needing Science rank 2 instead of Science rank 1, but no luck. Now I am at Science 2 and Gun Nut 2; my non-science mods needing Gun Nut 2 work just fine but any weapon mod involving Science is unavailable to me.

Help?