Chartmuseum unusable after deleting a chart

We are hitting a very annoying bug.
Our ChartMuseum is configured with a S3 bucket.
We are doing some cleanup, so deleting old charts
.
Once in a while, after we have Deleted some chart we are unable to perform GET call to list versions of a chart using the api.
We are hitting an error:
`{
"error": "NoSuchKey: The specified key does not exist.\n\tstatus code: 404, request id: XXX, host id: YYY"
}`

Restarting the pods doesn't resolve this.
The only way we have been able to fix this, is by going on the S3 and copy all the files of every namespace. Delete the current folder. And place back the files in the new folders.

Do you have any clues of how we can avoid to have this problem.
We are using the latest version of ChartMuseum (0.7.1)

Thanks for you help