Hi Deanna,
Its not a bug. Looks like the sorting arrow is hiding for you at the column you are looking at. Please extend the "width" of the column "contract-end" and you will see an "arrow-button" reflecting the status of Sorting.
On first click, the sort will be ascend and a blue ascending arrow is shown at the column name suffix. On second click, the sort will be descend and a blue descending arrow is shown at the column name suffix. On third click, the sort is removed and moved to default sort. The default sorting is by "Contract start" date, hence you would not see any sorting when 3rd click on "Contract end" date. On fourth click onward, above sequence repeats.
Regards,
Pavan
