"The connection was reset" when "Preview Changes" or "Update" clicked

Edit one of your pages and paste this line into it (anywhere) and see if it gives you “The connection was reset” when you click “Preview Changes” or “Update”…

‘x’ or ‘y’

It looks to me like the or is being parsed somewhere as a logical operator between two string variables/values, and this causes a crash?

I have a few sites with various WordPress versions, and it fails for me on WordPress 4.4.1 (WooThemes Canvas and Gadgetry themes) and 4.3.2 (Canvas) but is OK on 4.2.6 (Canvas)

This is NOT a server configuration problem as it only happens on the one page the change is made to, and as you can’t update the page with this edit in it you can’t get the error when just viewing a page.

When I first had the problem the sentence the text was in was considerably longer – I have whittled it down to the basics for this example. It is fixed by replacing the quotes by the HTML left and right single quotes lsquot; and rsquot;

Happy bug hunting, this one took me an hour to work out. ??

Kevin