To give an example which I came accross while working through the many subdistricts created in 1947. The Gazette announcement has the creation of the subdistrict Bang Phli (บางพลี), Bang Sai district, Ayutthaya province, which was split from a subdistrict named Ban Ko Bang Phli (บ้านเกาะบางพลี), so I suspected this subdistrict was renamed to Ban Ko (บ้านเกาะ) afterwards as that is the name of another subdistrict in the district. As I haven't found any Gazette announcement on this I checked the ThaiTambon page on Ban Ko.
ประมาณปี 2500 – 2503 ต่อมาทางราชการได้รวมตำบลบ้านเกาะ และตำบลบางพลีเป็นตำบลเดียวกัน ชื่อตำบล บ้านเกาะบางพลี ซึ่งต่อมาแยกเป็นสองตำบลตามเดิมwhich translates to "around 1957-1960 the government joined Tambon Ban Ko and Bang Phli into one Tambon named Ban Ko Bang Phli. This was later split into two Tambon as before again."
But as I now have the official document which states the split happened in 1947, the years given in ThaiTambon clearly must be wrong, or rather unlikely the same operation has been done twice. Sadly I cannot find the announcement on the merge of the two subdistrict or the name change for the remained subdistrict, that'd answer more questions.