Issue Action Module's Auto Resizing Not Working

Hello everyone,
I’m working on an Cloud app (using Forge ofc) that requires using Issue Action module.
Based on the document, when not specifying the viewportSize attribute of the module, the dialog should automatically resize. From that phrasing, I assume it should adjust both width and height, but it only worked with height when testing it out. Is this a bug or it’s an intended behavior?