The bloomberg article has more details. Based on the correspondence provided by both parties there wasn't an offer made by the domain owner. He suggested a price, but that by itself does not constitute an offer, or houses would always sell for list price.

Bloomberg quotes a corporate lawyer who claims that the $50k price constituted a "firm counteroffer," which could be accepted, but they chose the wrong expert to ask.

Generally, for contracts between corporations and non-corporate entities, legal formalities are required to make the contract binding. This almost means a signed written agreement where the terms of the exchange have been specified.

Between corporations, or between individuals, courts have been willing to relax the requirements for formalities (meaning, not requiring signatures, or not requiring a single document laying out the agreement between the parties). But between corporations and individuals, courts have been very, very insistent on observing legal formalities, due to the extreme power differential between the parties.

It's very likely that Jump will settle this case. Even if they somehow win at trial, the domain owner can simply appeal and keep hold of the domain name for years before the appeal is resolved.