PHPR 5.2 (4890) List Page Broken

After PHPR version upgrades (etc), I sometimes get "Page Broken" error on some list pages in browser. These particular pages have no custom javascript, however they usually have a small alteration to the layout. I do a normal "reset this page" in the editor tab, re-build, same outcome - broken. However, if I go back to the editor tab, select the HTML view, select all the code and delete it, then "reset this page", the code is regenerated, make my minor alterations, re-build, and voila it works. This is not a new issue for 4890, the same behaviour existed in 5.1.