Thanks for the clues, Lukas. We tried both suggestions with mixed but ultimately unsuccessful results. The x.y targeted click still missed using either of the suggestions. What we're scratching our heads over is this site isn't fundamentally different in its construction from the two dozen other sites we're monitoring and those have been running well since inception.
I went back to a product blog by Peter Kruty on "The Perils of Javascript". Peter suggested using the keyboard [tab and arrow keys] to navigate and the space bar to select. The t/a now runs successfully on the Player PC, which is good. What's weird is that it fails miserably when run from the WPM server, which is not so good. Still, it's running from the cloud instances and we're getting metrics, which is good.
I'd say this solution is the correct answer except for that last bit about it failing when run from the server. Any more clues out there? Please, and thanks...Fred