Hi Steven,
First i set up a brand new WordPress installation with Twenty Seventeen theme and only activated Advanced Ads. It worked as expected.
Next i switched to the theme we are using on the site. Advanced Ads continued to work as it should.
Then i went back to my local working copy of the site, where Advanced Ads was showing the problem, and started de-activating plugins. When i de-activated Connections the problem went away. When i re-activated Connections the problem re-appeared.
I you would mind telling me what version of PHP and WP you tested with, as well as what theme, i will try again, and this time remove all other plugins except the two that seem to be conflicting.
Just to be clear… this problem is occuring only for the second and subsequent save of rich text with and tags, where the parameters are using ordinary ascii double quotes, not curly quotes. Every double quote gets escaped with a backslash.