I use the eyeheight legaliser quite often. Only issue I had was with still images (with ken burns moves etc) rendering with illegal levels. It happened when I nested a progressive sequence into an interlaced sequence, so I could have interlaced scrolling credits with the rest of the doco having progressive pan and scan etc. Otherwise it has been very reliable, albeit super slow to render/export. I use the 'extra safe' setting. Have you got the plugin on an adjustment layer? I.e. It needs to be the last effect in the chain to work properly.