All Grafana data suddenly disappeared

Hi all. We are using Grafana open source docker image to run our Azure Web App. We have been using it for around 1 month without any serious issues, but today all of a sudden, we noticed that our Grafana was completely reset (No dashboards at all, no data sources, no teams and even default preferences were set to default values.) After further investigation, we understood, that the docker container in our Web App had restarted at approximately in same time period when the data was lost. Data loss is very strange behaviour since we have a volume attached to the container with Grafana. Any attempts to reproduce this behaviour also failed (we have tried to restart the container itself and even to use a different image). Fortunately, we have some backups to restore all the dashboards, but I will be glad to recieve any suggestions why such situation happened.