Screen taps not registering on certain iOS devices

I’m using a combination of AltUnity Tester and Appium to run tests on a media player app. Some of the tests interact with the media controls, such as pause and rewind buttons. Because the controls disappear after a few seconds of inactivity, I want to send a tap to re-enable them. However, the tap doesn’t seem to register on my iPhone X running iOS 13.6.

Our code for sending taps on iOS looks like this:

TouchAction<?> touchAction = new TouchAction<>(appiumDriver);
if (appiumDriver.getPlatformName().equalsIgnoreCase("ios")) {
        touchAction.tap(PointOption.point(screenSize.width/3, screenSize.height/3)).perform();
} else {
...
}

There are no error messages in the Appium logs. Any idea what’s going on?