The app is correct and we will fix the error for the web version in the next release.
We checked from our server side and 5 waterings were OK. When Netro finishes running a watering schedule, it will send a confirmation to the cloud server. In this way, the could server knows whether the schedules are correctly executed or not.
The exclamation mark means the cloud server did not receive the confirmation from the device. In your case, the schedules afterwards are all correctly run and confirmed so don't worry about it. It could just be a temporary network issues. But if that happens a lot please check the WiFi signal strength. If you use a WiFi extender, please make sure it is connected to the main router stably.