It appears that removing a buffer chest with a robot crashes the game, likely due to robots removing a different way than the player does, from what I recall hearing. That said, placing chests works fine, as does having them get destroyed by biters (didn't test explosions since biters worked fine) - I also tested replacing a storage chest with a buffer chest by bot, and that appears to work. Likewise, oddly enough, replacing a buffer chest with a storage chest works fine, even if removing it does not.

Updated.

Thanks, I can confirm that the update fixed the problem.

Edit: I've tried my best to break it more, and I can't find any other problems. Thanks for fixing the ones I found, this mod is very useful, thank you for sharing it with us as well.