Toasters are not spawning in missions. For example, Defend the Southern Entrance in Tidal Wave does not spawn any enemies. So now the mission is stuck there and has been for more than a month.
In co-op, players cannot hear or see the other player’s weapons or when they fire their weapons. Also, so toasters can hit one person but not the other (e.g. just fought two tanks in co-op and they couldn’t hit/damage me while the other person saw them hitting me with .50 rounds)
If forum search didn’t produce any same/similar results, make a bug report topic where you report one bug per topic and by following this guide: READ BEFORE POSTING - How to Make a Bug Report
These kind of mash-up topics that include several bugs all together, without proper bug reporting template, are hard to monitor and are frowned upon.