Bizarre softball rule

In the Liberty League softball game between Viewpoint and Santa Clarita Christian, the umpire made a bizarre call in the seventh inning.
The umpire said the Viewpoint catcher was giving her pitcher signs when the pitcher was not on the rubber. Apparently this is against the rules. If so, it's a silly rule.
The umpire gave the Santa Clarita Christian batter two balls and she ended up walking, putting the potential game-winning run on base.
Viewpoint's pitcher Micelle Lesser got out of the inning and hit a home run in the eighth to win the game, but the umpire's ruling in the previous inning almost cost Viewpoint the game.
Viewpoint's coach said her catcher doesn't even give the pitcher signs. Her pitchers get signs from the coach.
The umpire warned both teams for giving signs when the pitchers were not on the rubber.
This is a bizarre rule and if it exists, it should be re-evaluated. Apparently the catcher can't give her pitcher signs unless the pitcher is on the rubber. But there is no rule that says the coach can give a pitcher signs when she is not on the rubber.