[2021] Invaded Roosevelt Island Bugged

I completed Roosevelt Island (invaded) earlier this morning and expected "Shorty" to drop his exotic part of the sniper rifle. It didn't drop. I have the other parts and just need this to then get the blueprint to build the exotic.

There appears to be a bug here since it didn't drop. Can you raise this so it can be looked at as others may be suffering the same bug. Additionally is there anyway I can be provided this part as way of a grant. I have screen shot the completed mission but not sure how to add it to this thread from my desktop

Thanks