What made the tracks unusual was that the marks were manus only, referring to footprint impressions made by front limbs, not the rear limbs (known as pes).
The alternative view to explain manus-only tracks like this is that the forefeet of sauropods (supporting more of the animals' body weight) are all that leaves track marks on certain kinds of ground surfaces, as the rear limbs, supporting less weight, leave less impression on soil and sediment.
While that might now be the generally preferred interpretation of manus-only sauropod tracks, the case for dinosaurs treading through shallow, shoulder-height bodies of water on their front limbs (with their rear limbs not reaching the ground) has never been definitively ruled out.
While we don't know for sure what kind of sauropods left these manus-only marks, the researchers highlighted the possibility that it could be a different kind of dinosaur to those responsible for other manus-only footprints previously seen in the Glen Rose Formation.
"Greater differential pressure exerted on the substrate by the forefeet than the hindfeet probably explains the Coffee Hollow trackways, like other manus-only sauropod trackways, but the possibility that they indicate unusual locomotion cannot at present be ruled out," the authors wrote in their paper.