Campaign: When lowering difficulty mid-mission, revives are lost

In the campaign, your difficulty determines how many revives you can have.

• Recruit: 3 revives
• Regular: 2 revives
• Veteran: 1 revive
• Hardcore: 0 revives

You are allowed to switch difficulty during missions on the fly without a loading screen.

When switching campaign difficulty mid-mission, revives are lost if you switch to a higher difficulty then back to a lower difficulty. So if you start at a low difficulty, then switch to a higher difficulty, then back to the low difficulty, you will lose revives when you switch to the high difficulty (they will be capped at the limit of that difficulty), which is appropriate. However, when you switch back to the low difficulty, you don't get any revives back, even if you haven't spent any revives by getting downed.

So, for example, you can start a mission on recruit with 3 revives, switch to hardcore, then switch back to recruit, and you will have 0 revives even if you haven't been in combat yet.

It would be more appropriate behavior if you gained revives when you switch to a lower difficulty, just as you lose them when you switch to a higher difficulty. For example, if you play on veteran, get downed once (now you have 0 revives left), then switch to recruit, you should now have 2 revives, not 0.