I found a behavior on SharePoint 2013 farm that really surprised me. I'm just looking for confirmation that this is a widespread issue and not just a quirk of this one farm.
Setup: Create An out of the box Custom List with a multiline text field called "Update" added to it with the enhanced rich text option set. Also, add two Choice fields called "Category1" and "Category2" and give them any choices like A, B, C and a, b, c for example. Now add a few test items with various categories and then create a new view with group by set to "Category1" and "Category2" and the default collapsed option.
Problem: Now add a test item with Category A and a (so you can find it) and in the Update field type some text with a quoted phrase in the middle, like: This is my test text with "a quoted phrase" in the middle. Go back to the view you just created and try to expand the A-a category ... mine hangs with the phrase "working on it"
Research: I fiddled with the debug view and found that the javascript was crashing at a JSON.parse(c.responseText) causing the UI to hang. After hours of adjusting the content in my list, I narrowed it down to the quotation marks. It looks like they aren't properly serialized for JSON by the enhanced rich text field.
Question: Could anyone who has experienced this problem please throw a response onto this post so I know it isn't just my farm? Then I can go ahead with a bug report to MS. I would also be interested to know if this is still a problem in SharePoint 2016 or SharePoint online.