We're pushing out an update to fix some of the issues you've been encountering in Invasion.
However, do note that most of these are server-side and so you'll need to wait until the server hosts update their files until you get the full benefit!
Our (almost day 1) patch notes:
- Shields now recover HP along with players at the end of each wave
- Reduced "it's almost harvesting season" sound frequency
- Fix for knockdown mace hitting mounted enemies and causing visual error
- Enemies captured with team change dart no longer visible in drop assignment UI
- Fixed potential crash causing issue on servers in Invasion mode
- All dropped items are now useable by all troops
- Invulnerable helmet is now more protective (but still not actually invulnerable)
- Disarming throwing axe can no longer by turned into an instakill knife
- Additional fixes