In one hardcore contract, I picked collatoral kill - firearm as the prestige objective. I chose to bring my ICA Bartoli Woodsman hunting rifle covert. When I spawn in the loading bay, to my panic I was not holding e briefcase.
Luckily, I managed to use another weapon to complete the contract. But when I returned to the safehouse, the weapon was still not there!
I suggest you to post bugs in a special thread which is monitored by IOI stuff, or send them directly to IOI Support.
Thing is, they don’t read the whole forum and this your report might go fully unnoticed.
If you really want this to be considered, use this thread: