Steps to reproduce:

1. Launch the game and join a world
2. Open autoswitchAttackAction.cfg
3. Add a line block@immersive_weathering:grass_growth_replaceable = any
4. Notice how mod stops working, trying to erase this line also doesn't work anymore
5. Run /autoswitch cacheSwitchResults true (we didn't change anything, just made the mod rewrite configs)
6. Notice how it replaced our block@immersive_weathering:grass_growth_replaceable = any
   with block@immersive_weathering = grass_growth_replaceable = any
7. The mod won't let go of block@immersive_weathering = grass_growth_replaceable = any until you fully exit the game, save the config and launch the game again

Potential solution:
Your mod tries to "fix" an invalid config, which is a bad thing to do. It would be better if it ignored invalid configs and went with default settings instead.

Something could be done to potentially make this more graceful, but for now the issue is the :, replace it with !.

Thanks for the report.