...snip...
They dedicated a tap ( cryptobetting) on their wallet to 1xbit.com and they also have a promotional code that gives 125% on first deposit to new users who register using the code "Mycelium", they are not only paid to advertise but it seems like they are in partnership with 1xbit.com. money is powerful if you ask me. I don't know what options this belong to but Mycelium are fully aware of the advertisement and reporting to them would lead to nowhere.
Check the upper part of the image.
If there's promo code which refer to mycelium, then only 2nd/3rd option possible. But since Mycelium have decent reputation, it's possible they didn't do proper research. Unfortunately they don't use social media (according to
https://wallet.mycelium.com/#support), so there's no way to ask about it and get answer publicly.