That question does (or did) indeed have a pending suggested edit attached to it. While an edit is pending, you cannot make further edits to it.
The edit link is greyed out on the main site and has a tooltip that displays when you hover over the edit link (for those who can't vote to approve/reject it), which explains that there is a pending edit and you cannot edit it.
Since mobile doesn't really have any way of "hovering" to get that tooltip, the edit link just isn't displayed (which used to be the normal behavior on the main site when the link didn't get greyed out). I suppose they could display the edit link greyed out on mobile, but that would cause just as much confusion as not displaying it.