How about providing some additional details, as it appears the issue only impacts a small amount of users. A lack of information makes reproducing/troubleshooting/fixing the problem you are having difficult for devs.
Platform/Device:
OS and Version:
Browser and version:
Browser extensions/add-ons:
Have you tried clearing cache/cookies/storage?:
Are you using private/incognito mode?:
Does your browser clear/cleanup data when closed?:
Does this happen when using another browser and/or with a clean browser profile?:
And just for reference MD does store reader settings in 'local storage'