Odd characters on Youtube pages

[Tymme]

Youtube video pages are getting covered with odd characters/graphics, only when this plugin is active (when page/site/globally overridden, chracters disappear- see attached screenshots).

Using Chrome 46 (up-to-date, though has been an issue since about v43? few months or so), Windows 10. Extension v2.144 from Chrome web store.

Have removed and readded the extension, disabled all other extensions, cleared all data, even reset chrome and wiped appdata/programdata.