You’ve reset the Blacklist, but maybe you need also to clear out all references to those plugins in VST2xPlugins Cubase(x86_64).xml. The “sledgehammer” approach would be to simply remove that file (but then you’ll have to rescan all your plugins)… but that is the thing to do if you don’t feel happy about rolling up your shirtsleeves and attacking that file with a text editor 
. (find the plugin name, then delete from the line “”, somewhere above it, to the corresponding line “/”, somewhere below it.)