What does the phrase lemon on mean in this context? Is it an idiom? What is its correct usage?
Excerpt from where I read this phrase:
... Hold on, for this deal, one that does not exist anywhere outside a very fertile imagination, could actually be a lemon on at least five counts. These are the lures that should alert you and beg a recheck before you book the deal.
Source: How to Avoid Common Travel Traps