I’m getting an error when updating member records. Here’s the error message:
Converting circular structure to JSON → starting at object with constructor ‘Object’ | property ‘subscriptions’ → object with constructor ‘Array’ | index 0 → object with constructor ‘Object’ — property ‘tier’ closes the circle
Ideas?
Update Ghost to latest 
I was also getting this error. A workaround for me was removing the subscription and then making the change, saving the member’s record, and adding the subscription again. That was only possible for me because I was doing things with comped members. It may not be possible for you if you are trying to edit a paid member.
However, I have noticed that the problem no longer exists for me, and I do not get the error.
As the previous user said, try to update Ghost. I am not quite sure what was causing this problem, but an update might work. Failing that, try to run Ghost Doctor and see if there is anything wrong with your installation specifically.
Sorry that I could not be of much help; I had just wanted to add my voice to this problem to make it gather weight so that the tech team could take a look at it.
Mel
I have my site on Gloat, so I can’t update it myself. I reached out to the owner, and he said he had just updated to the latest release.