Azure Function App files went missing after months of deployment

Question

I deployed 4 function apps using VS Code Azure Functions extension and it has been few months of deployment. There is 1 time trigger and 3 blob trigger function apps. All the function apps executed till last week. All of them are supposed to execute once in a week. But this week none of them executed. One of the blob trigger function app has all the files and code as it is but others have missing files like function_app.py and requirements.txt. The host.json file include the content which used to be there by default instead of the one that I deployed. There is no change made in any of these function apps and it happened on it's own. All of them are Consumption Plan. Help me understand this situation. Even there is no traces in activity log.