I am rather hesitant to join this debate at the moment as I haven't seen it in the field yet.
But this bird from the photo's seems to me to have the feel of semi-p, it just looks a bit to round and dumpy to me. Also to me the shape of the scaps
looks more like anchor than arrowhead.
Yes at times it looks leggy and long-billed but there are some Semi-p pics out there depicting some bills of a length any small peep would be proud of.