This happened with a Russian lesson imported with the Firefox add-on. When it encounted a quoted phrase starting with «оснащением it included the Russian open-quote symbol “«” as part of the word. I was offered the opportunity to make a link for «оснащением but could not make one for оснащением.
Another really bizzare thing happened when it encountered the phrase “оборудование и программное обеспечение”. I already had lingq for the phrase “программное обеспечение”. The reading pane showed “и программное” as the linked phrase, but in the hints pane it showed my lingq for “программное обеспечение”. See below.
It also has highlighted in blue numerals and punctuation, such as “—”, but when I try to ignore those it pops up the alert “SyntaxError: JSON.parse: unexpected character at line 3 column 1 of the JSON data Please check your Internet connection and visit our Twitter feed for system status updates.” It lets me ignore real words, though. (The “—” and “2014” do not show blue below because I turned the page, and I guess they got added as known “words”.)
[Edit: I mistakenly said this was imported with the Chrome add-on, when in fact I was using Firefox.]