Me and 3 friends have fulfilled the requirements for this about 5-6 times now, each being far below 20 seconds. Lowest we recorded was 15s. As of the new update, we’ve done every other legend base game challenge without issue, but this one refuses to complete for us. We’re convinced a recent update has broken this entirely, just like what happened on PC which recently got fixed. (I believe cataclysm was the only way to do it before the fix).
I’m not sure if we get the exact same updates as PC despite it bugging out things like this, I would’ve expected it to be revised if it was already a known and fixed issue. I hope this can be fixed soon as it’s our last challenge for the Portrait.