Update: MLB has confirmed that this entries on the transaction and roster pages were an error on their part, and that the Pirates have not yet made a decision on whether to exercise Kang’s option.
It’s a correction; the club has an option that hasn’t been decided yet.
The Yonhap News Agency is reporting that the Pirates have not exercised their 2019 option on infielder Jung-ho Kang. This was based on his being listed as having elected free agent on the Pirates’ website, although in a quick search I was not able to verify that, but Kang is not listed on the active or 40-man rosters.
EDIT: Here is a screenshot from the Pirates’ transaction page: