Could you let us know on which devices the recently played artists don't update and on which devices they do? You also mention that it will work for a few weeks and then stop. Are there any steps you take to make it work for a while?
We'd also like to know if you are talking about the Recently played which you can find in the app, or the Recently played on your profile. Because the second can be switched off in the settings so be sure to check that.
Let us know what you can find. Looking forward to your reply.
We are aware of an issue with the app and are currently investigating it. Feel free to contribute in this topic where we gather information from affected users and keep everybody up-to-date. We'll get this sorted as soon as possible.
Sorry for the inconvenience. Let us know if you have further questions.