I have this issue as well, plus all Signature ammo disappears when I arrive as backup and conditions for enemies to drop Signature ammo do not take effect until halfway through a mission. I opened a thread on my issues good to know it's not just me. A temporary workaround is to activate a different specialization and then re-equip the one you were using. Ammo gets refilled. Annoying to hold F key three times or so but it works after you reload your game. You can also fast travel during a mission to Base of Operations, switch Specialization, switch back - ammo refill.
-junkpilezero
Hello Ubisoft,
Here's what happens:
1. If you relogg = lose all special ammo
2. If you join someone elses session = lose all special ammo
3. If you enter the DZ = lose all special ammo.
The only one that makes sense is no 3 of course.
The silly part is that you can go to the White House BoO and switch to some other spec and BAM, full special ammo.
Then you can switch to the spec you wanted to run, BAM, still full special ammo.
So the fact that you lose all special ammo when joining someone session or relogging makes absolutely NO SENSE (barred no 3).
How hard can it be to fix something like this, or to even realize this isn't the way it should work.
/Sgt.Multipass