Web Compatibility Support • iframe from system.promio-connect.com is hanging and forever increasing the memory usage of the browser

Example URL where you can see hang and memory bloat (scroll down far enough to trigger the website to load the offending resource): https://www.dw.com/en/filipino-nurses-i ... a-68918928

There's nothing relevant in the console outputs, so I'm not including it here.

33.1.0, Windows x64 mainline, fresh profile.

EDIT: Aha, narrowed it down to this iframe of an mailing list sign-up being loaded by https://www.dw.com/webapi/iframes/widget/en/66496979: https://system.promio-connect.com/regis ... 2F66496979

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