It looks like Webkit is complaining about memory resources being scarce .
UIVM memory was already bumped to 256MB with the Zeus upgrade, it seems to be still insufficient for the requirements of WebkitGTK.
UIVM, webkitgtk - 2.24.4-r0.
Install OpenXT 10 or later.
Create a guest.
Monitor UIVM for Memory pressure relief messages.