Thanks for your effort performing the requested testing.
To be clear, you’re saying that, with all your plugins activated and the Twenty Sixteen theme active, this issue is resolved.
If that’s correct, your theme is conflicting somehow, in which case you should make sure you have the latest version of that theme and then, if it’s still happening, you should report your detailed findings to your theme author, especially if it states compatibility with our plugins.
Please let me know what you find out.