In regards to the problems presented by Kyle_K_ski a few pages back, I'd just like to note that we can confirm three more cases of strange grenade behavior happening for two friends and myself. Between the three of us playing together, we used various installation methods - converting based on a Steam installation with PWS, converting with PWS based on a properly patched disk version, converting manually based on a properly based disk version. The user who had converted from the disk version using PWS also tried doing it manually, resulting in the same outcome. Only WW2 grenades work properly, even if thrown by modern units. Likewise, modern grenades immediately drop to the ground even if thrown by IF units. This problem happens even when only the absolutely essential mods needed to run IF are installed. We've checked very carefully to follow the installation guide, so I think it's unlikely that the issue is a faulty installation. Problem happens both when we try to play together as well as when trying to throw grenades in SP.
The error can of course be avoided by deactivating IFA3 while playing modern scenarios, but on the off chance that one does want to mix assets (or simply wants to avoid having to restart the game between playing different missions), that's of course not possible.
Anyway, just wanted to confirm that other people are also having this issue. Thanks for maintaining this mod!