Demonetisation dates error

Since this site was created in 2007 I wonder nobody has pointed out the error I found today ! When a date is entered for a demonetised coin the three boxes appear and are marked  mm-dd-yyyy
 The other day I was entering some dates in there for 1st August 1969 so put  08-01-1969 going by mm=08 and dd=01 and yyyy=1969 and clicked on  Modify data  and carried on.
 However, today I had two coins where I was going to put in 31st December 1869 but 12-31-1869 did not get accepted. Though guessing why, I successfully amended to 31-12-1869
 So please amend the pages to show  dd-mm-yyyy  after the boxes, as in those instances like I had where both day and month are less than 13 then entries would be unknowingly put the wrong way round.
 Thanks :)

                                                  

https://en.numista.com/catalogue/pieces3310.html

 This already has just the year 1960 entered in demonetisation, and is not locked, so when I added 31-12 as well then after  Modify data  was pressed, the page above still reads just 1960 instead of 31-12-1960

 Last month I had a similar query as to why my amendments had not been displayed after  Modify data  was pressed; I found out the Obverse engraver for these six below was Stuart Devlin

https://en.numista.com/catalogue/pieces3827.html
https://en.numista.com/catalogue/pieces16492.html
https://en.numista.com/catalogue/pieces7845.html
https://en.numista.com/catalogue/pieces4103.html
https://en.numista.com/catalogue/pieces2631.html
https://en.numista.com/catalogue/pieces6038.html

 Other coins of Singapore could be amended, just not those six. Could someone please amend all seven (if my details are correct of course) and explain why such do not get Modified ?!