Gazette announcement published before approval?

The announcements in the Royal Gazette usually have three dates. One is the date of publication, another the date when the announcement becomes effective, and finally the date when the announcement was approved. While the date of becoming effective can be before the publication or even the approval, one would expect that the publication always follows after the approval.

Yet, I now ran across one publication which apparently was published before it was signed for approval. The creation of the subdistricts Phu Toei (พุเตย) and Sam Yaek (สามแยก), Wichian Buri district, Phetchabun in 1967, VOlume 84, Issue 38 ง, pages 1407-1412 was published on May 2 1967 and became effective on May 1. The strange is that in the very last part it reads

ประกาศ วันที่ ๒๔ พฤษภาคม พ.ศ. ๒๕๑๐
ถ. สุนทรศารทูล
ปลัดกระทรวงมหาดไทย

which translated to "announced on May 24 2510 [1967], Th. Sunthorn Santun, Minister of Interior. So this announcement was published in the Royal Gazette three weeks before the Interior Minister was about to sign it. Either this was an unnoticed mistake and should have read "April 24", or it was anticipated that he will sign this announcement no earlier and no later than that exact date, but the publication could not wait.