Defects in Dos Equis Ambar bottles are causing problems for Heineken USA, the Mexican beer's U.S. importer.

Heineken on Wednesday announced a voluntary recall of 6 and 12-packs in 43 states after the company's routine inspections determined a defect that created the "potential for small grains or particles of glass to separate from the inside lip of the bottle and fall into the liquid."

At the same time, the company is pulling new ad spots that featured Ambar, a dark lager that makes up about 30% of Dos Equis' total sales, according to an AdAge report.

The recall comes at a really bad time for Heineken, which recently stocked its "Popular Beers of Mexico" pack, a sampler that included several bottles of Dos Equis Ambar, just in time for Cinco De Mayo. The recall is affecting major markets like California and New York, so if the company isn't able to restock shelves in time for the holiday, it could represent a major loss for Heineken.

Dos Equis is an important brand for Heineken, which bought Cuauhtémoc-Moctezuma Brewery, where it is made, in 2010. Since then American sales of the brand have risen steadily, with sales up double digits last year.

The snafu is also a prime example of the problems that can arise for importers. While the bottle was caused by a third party distributor, it's Heineken that will have to deal with the recall headache.

UPDATE: We heard from a Heineken spokesperson who said that the recall is a "very manageable situation" and that store shelves will be fully stocked with Dos Equis Lager for Cinco De Mayo." She added that they do not expect a signficant financial effect from the situation.