qt5-webkit crashes when searching on duckduckgo

Hello QT devs,

on two computers running Arch Linux, Qupzilla (which is based on qt5-webkit) consumes LOTS of memory when doing a simple search on duckduckgo.com. For example on my Laptop, the ram usage is about ~200MB with qupzilla open and some tabs. Then I do the search and it goes up to 3GB I've even had to reboot both machines because of that.

I've also tried downgrading to 5.3.2 and it didn't help.

In the qupzilla tracker [1] I was told to report this upstream.
[1]: https://github.com/QupZilla/qupzilla/issues/1605

Thanks!