UPS (NYSE:UPS) may be in trouble with its labor unions, right as the crucial holiday season approaches.

While voting among its labor-union members on its national master contract and supplemental local and regional contracts earlier this year saw the national contract passed, this agreement cannot go into effect until all regional and local contracts are approved. And with 17 local and regional supplements rejected -- which DC Velocity reported to be the largest number of contracts ever rejected by the Teamsters in the 110-year history of the organization -- this could spell major continuing trouble for UPS.

In this video, Motley Fool analyst Blake Bos takes a look at one of UPS's most essential local unions, which is responsible for its UPS Worldport location, and discusses the degrading relationship between UPS's management and its employees.

Blake Bos has no position in any stocks mentioned. The Motley Fool recommends FedEx and United Parcel Service. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.