Sometimes, my table of contents is doubled. If I wait some minutes, I only see it once.
An example:
What can I do to see it only once?
Are there any other users, who have the same problem?
Is that from some code in the YAML? Is that a plugin creating the toc? With a little more info, someone may be able to help 
Yes, “number headings” is the plugin that makes the toc.
Here are more details: