In a recent update (ARC build 209) Roon added single-sign-on, and this uses a browser window to log in (as was already discussed further up, by the way). So on an iPhone/iPad this is most likely Safari. If you configured a different default browser, perhaps it uses this one. Might it be possible that your iPhone and iPad have different default browsers?
This is from the release notes;
This is from my iPad right now, logging into ARC for the first time, with Safari as the default browser. It might not obviously look like one, but I think this is a browser window, note the address at the top. Does your login window look the same, and is it the same on iPhone and iPad?
The current ARC version is 1.0 (build 220) production. Is that what you have?
It could, but where is it? If on the phone, then it definitely has the potential. If on the router, one would think that it affects the iPad in the same way.
This probably won’t change and I don’t understand how it defeats the purpose of listening on the go. The point is to output to the phone (or tablet), and from there to the outputs that the phone has. This could be a headphone jack on devices that have one, Bluetooth, or via USB. When using USB you can attach a little mobile DAC as well (or a large one). On iPad/iPhone you can use AirPlay from the device controls, and on Android you can use the device’s Chromecast.
It would be nice to additionally have Chromecast and AirPlay within the app (so that Apple users can also use Chromecast and Android users AirPlay), but this might be added in the future.
Is this with ARC or regular Roon now?