TUA-Ump

Heading up for Week 10, along with 6 or 7 other guys from our Association! It's our annual vacation together. Thrilled to again have my son coming up to umpire - we have a great time up there. Really wish I had enough time to do multiple weeks.

Bases loaded; batter hits a ball straight down that comes to rest on home plate. Catcher grabs the ball with his bare hand, then throws to first to retire the batter/runner. Question is - does his grabbing of the ball from the plate constitute a legal tag of the plate for the force out on runner from third? Umpire ruled that it did not constitute a tag, that picking up the ball and tagging the base needed to be 2 separate actions. Appreciate your thoughts and comments.