Bearing in mind the fact that the linocut printing process by default is handmade and could involve slight variations (due to the amount of ink rolled, color texture in the printed result, roller pressure on the press, the paper texture, the presence of marks that could provide an unique effect, and so on), and also the fact the the artist is the only one who will decide if the result meets the standards, should we consider a series of prints made using the same lino source, the same ink, and the same paper a Variable Edition if there are slight variations in color consistency on the paper?
I've found an article here but I'm not 100% sure where this fits into the Printer's marks section.
LE: I also have found a great example here. The author accept the differences considering these unique forms adding a remark: Please note that [...] due to the handmade process and characteristics of ink, natural differences and irregularities will occur between prints.