In context: Amazon made a somewhat controversial decision prior to the holidays when it banned its third-party sellers from using FedEx Ground and Home (Air was still usable) to deliver their products. Though FedEx insists the ban had a "minuscule" impact on its business, the timing was decidedly inconvenient. The holidays are easily the most crucial time for product sales and shipments, and thus, they're quite important for companies like FedEx.

Amazon's decision didn't come entirely out of the blue, of course. The company itself claims that the FedEx ban was a result of "declining performance" from the shipping giant. However, it's possible that the ban could have been retaliatory in nature.

FedEx had ended its ongoing relationship with Amazon proper earlier in 2019, citing concerns regarding the retail giant's own expanding shipping infrastructure – FedEx wanted to avoid working so closely with a direct competitor.

Even Amazon would likely admit that this reasoning is sound, but tech companies have been known to hold on to petty grudges from time to time.

Still, speculation aside, it seems Amazon has decided its rival shipping firm has been suitably punished for the time being. In an email sent to its merchants (viewed by CNBC), Amazon stated that FedEx's delivery performance is once again meeting its lofty expectations, so the restrictions have been lifted.

Third-party vendors can once again use FedEx Ground and Home to ship their products, while still qualifying for Prime classification. Some sellers may remain frustrated, of course. After all, many were forced to make potentially-unwanted changes to their shipping infrastructure right before the biggest sales season of the year.

However, for others, this news might take more of a positive, "better late than never" tone. A stable relationship between Amazon and shipping firms like UPS and FedEx is ultimately a good thing for sellers, as it gives them more options for getting their products in front of customers.