Files downloaded from https://api.telegram.org/file/.... according to data from getFile, randomly empty ... and then not, later

[php4fan]

This exact sequence of events happens to my bot from time to time:

• my bot gets an update about a message containing a message.animation field
• my bot immediately does a request to getFile with file_id corresponding to the animations file_id
• this gets a response with a file_path field
• my bot immediately does a request to https://api.telegram.org/file/bot<MY_BOT_KEY>/<file_path> with the file path from the getFile response
• the result is a 200 response and a successful download of a 0-byte file.
• a few hours later I find out about this and I manually download the exact same url (the one that returned the empty file) from my browser on my computer, and this gets me an actual non-empty file.

In one case it was an animation, I'm not sure if that was the case in all cases, it could have been photos or videos.