If carbs are entered into HealtKit and then modified a short time later, Loop will count both the first entry and revised entry in total COB. This can present a dangerous situation indicating more carbs ate than in reality.

This is incredibly easy to do with a 3rd party app like myfitnesspal that writes carbs to HealtKit. Example to reproduce is to add a breakfast item with carbs in myfitnesspal, then get distracted for 2 minutes, then add a second item with carbs. The entry in HealthKit will be updated with the full meal that happened at the same time, however Loop with consider total COB to be the first item and then the full breakfast (first and second item). The details in CarbKit show up correctly, however the total COB is incorrect per the screenshots below.

The only way I have figured out how to fix this issues is to kill Loop app right away and reopen it before an artificial high temp gets out of hand.