My friend gave me a tactic to solve and said I wouldn't beat Stockfish level 8. So he got his phone with Lichess app going, set up the position in position editor, we selected play against computer and that it is WHITE's turn but the app went crazy and moved as black although I should be the first one to go.
Here is the demonstration: https://youtu.be/8X4mjhsi_uM and sorry that the app language is not in English.
We then tried setting that black is to start and the computer waited for us to make a move as black. But whatever we did, we couldn't start the game as white.
I then went on the PC and of course beat the Stockfish but that is not the point.
[Offtopic] There is also no Ultrabullet raiting showing on Profile on the mobile app, which I think should be good to add @thibault .