I found a problem when saving tags that if they contain characters like " (double quotes) if you keep re saving the "edit course settings" (for example) it keeps adding encoding to them.
1) go inside a course and click on "Edit Course Settings"
2) add new tag (a " b) , press Enter and Save form
3) go inside "Edit Course Settings" again, check on tags (they look the same) and click save again on the form.
4) If you go again inside "Edit Course Settings" this time tag is showing like "a " b".
If you keep repeating the process it keeps adding a " ;amp" to the tag.