The Executor is a beautiful ship when it fills the frame but as a lone dart in the distance it doesn't look very imposing flanked by a few more ships it might look a little less feeble in that particular sequence.

This could be it!!

The Executor generally serves as a command vessel to overlook operations (strategic objectives) while the Imperial-class star destroyers engage in pursuits (tactical objectives) as shown in the movie before. The Executor isn't as maneuverable as an Imperical-class SD. It is misplaced in that situation to stop the agile Falcon.

What's wrong in the original scene is: In space there are three dimensions to escape the path of a vessel. I would try to escape the Executor by passing its stern. Instead, with all possible directions to escape the Executor's path, they are directly flying towards it and then crossing its bow where the Executor should have its most firepower and tractor beams. That's wrong tactically and I never understood why our experienced heroes were doing that. Maybe for allowing Luke better mind communication with his father? Odd!

A more logical solution would be: Leia spots at least three star destroyers and because they are encircled(!) they choose to escape by closing in on the least maneuverable SD (the Executor) to flee from the more maneuverable Imperial-class SD-ships. The Executor's mass is blocking the pursuit of the other star destroyers. That tactical situation would explain why the Falcon passes the bow of the Executor when it could have passed it's less defended stern (because it is covered by another Imperial-class SD).