Error 202 occurs even during normal App Engine operations. Usually it's nothing to worry about - the next instance will open and handle the requests.
However if you're seeing a lot of 202 errors, you may be hitting memory constraints. Try using a
bigger instance size, using smaller input files, writing to the datastore in smaller batches, or setting a sleep time between processing a batch of data. Do you see a specific error while running? For example, do the errors occur while processing a particularly large entity, or a large batch of entities, or after a certain amount of entities have been processed, etc?