[2020] I unlocked the milestone for the DL-18 but never actually got the crate. It also isn't greyed out like other completed milestones. Any tips?

We are aware of the ongoing issues with milestones not rewarding the rightfully earned attachments or weapons connected to those milestones.

This has been passed onto the team, when we receive an update we will relay it as soon as we can and hopefully restore this functionality as fast as possible.