Mechanic task disappeared after accepting

All has been working flawlessly up until this point. I accepted the task Gunsmith - Part 19 from Mechanic, built the SVDS, and when I went to go turn it in: the task is simply not listed anywhere in the list (screenshots on imgur). I've tried googling the issue, and only found to clear the cache. I've cleared both the client's temporary files via the launcher, and even cleared the server cache (after backing it up).

Updated the entire SPT, and the issue is resolved.

I don't check back onto this hub often at all, so I didn't realize I was that out of date lol