I am having the same issue with a US radar GIF as well. It does not appear to be updating the radar image properly, however the timestamp of the image in the upper left-hand corner is correct, nor is the application throwing errors, so it is getting new data from the server.
Some of the data appears to be okay, however there is a rain overlay that is simply stuck in several frames of the GIF. Have attempted clearing cached data, deleted the saved image, rebooted image hosting the service - all with no change.
I would like to get an update regarding this information as well.