Lets say normally toolA renders (it has its own outputTemplate defined in its meta) but it returned isError true in the toolResponse, mobile ChatGPT app does not try to render (iframe not even popped up in the screen) whereas desktop and web clients pops up the iframe and tries to load the resource. I believe the desired behaviour would be the one that mobile does. So, I think this is a bug for desktop and web clients.
IOS version: 1.2026.188