You're not insane. Expensive is not a term usually connected with lambrusco, which is an Italian wine which is not typically appreciated by serious wine drinkers. The "Lambrusko" spelling is not unusual in Germany or Eastern European countries. Although it is not nearly as common as it once was, it is not unusual for wines made in France or Italy to be purchased by a negociant in say Germany, Belgium or England, shipped to the negociant in bulk (usually barrels for good wine) and for the wine to then be bottled (often after blending) in the negociant's cellars for sale. In your case, it might have had a label entirely in German if the wine was imported by a German negociant for an entirely German clientele. As an aside, the best bottle I've ever had of the 1955 Château Ducru-Beaucaillou was bottled in Belgium by a negociant who was known (in the day) for reliably importing bottling top growth Bordeaux. So, it's quite possible yours was an particularly well thought of exemplar of the negociant's Lambrusko.