If we have two templates, for example a normal "Template:Cite web" and a strange "Template:Cite web:Strange name" (Книга and Книга:Биологический энциклопедический словарь) then ProveIt will think that the template is "Cite web" rather than "Cite web:Strange name".
It seems that with certain template names, the gadget fails to scan them correctly. This is probably due to the extra colon, but it may also be a regex issue or encoding issue.