Huh. I must admit I didn't even know you could use medpacs from the inventory screen, I always use the shortcut bar. But you're right, they aren't functioning when used from the inventory. I'll look into it.
Edit: Okay, that was an easier fix than I was expecting. Looks like TSL does medpacs slightly differently from K1 and I hadn't noticed when porting it. Fixed version's up now.