I imagine it won’t get shutdown for everyone as that’s triggered by getting the thing to draw more than 120 mA via the lightning/USB adapter.
Ironically, it is the lower-impedance headphones that “common wisdom” say are easier to “drive” that are more likely to trigger this. These draw more current than high-impedance cans, and that’s really where the problem lies.
At idle (nothing playing, no headphones connected) the Cobalt was pulling 60-63 mA. That jump up to 72 mA with simple 16/44.1 content being played, and as high as 90 mA with more dynamic content and MQA decoding (again with no headphones attached).
That leaves very little headroom for driving the actual load, and a low-impedance headphone, even of moderate to good sensitivity, can draw an additional 30 mA without much difficulty and without a need to play at high volumes.
The Rosson RAD-0, for example, at just 85 dB SPL (my normal level), would cause a shutdown with bigger peaks (105-106 dB) and crescendos in music on a reliable basis from the iPhone, where as the Red I’ve never had shutdown at all no matter what I did with it.
So while this is a non issue on a PC or Mac, and less of an issue with Android phones that have higher USB-power power limits, on iOS it’s a potential problem that didn’t seem to exist before.