I found a difference in appstudio V4 and V8 meta tags:
V4
meta name='apple-mobile-web-app-capable' content='YES' />
meta name='mobile-web-app-capable' content='yes' />
meta name='apple-mobile-web-app-status-bar-style' content='default' />
V8
meta name='mobile-web-app-capable' content='yes' />
meta name='apple-mobile-web-app-status-bar-style' content='default' />
By editing index.html on my server to look like V4, Add to Home will again allow full screen, albeit without the correct icon. However, it reports screen height incorrectly.