Steam Link touch input not recognized as a controller

On iOS, both an iPhone and iPad mini, I'm unable to get the onscreen touch controls to be detected as a controller. Instead they automatically switch to a keyboard and mouse based config, and PoE says it doesn't detect a controller.

Using a controller configuration this way works in other games, and it used to work before (~3-4 months ago since I last checked). GeForce NOW worked as well. Connecting a controller (xbox) works as expected. I have scoured through settings and have not found anything relevant. Is PoE just not recognizing it?