Reference field moved to a custom field at the bottom

We have sometimes a so called “Yearly contract” with our customer. So far i always use the #reference field on top of the sales order. (see first pic)

now i found out that on all sales order this field somehow move to my “custom field” which i called “shipping date” without doing anything (see pic 2)

There was no update which could have caused this. I assume someone in your business has set reference number to #SO15026 and put shipping date into custom field.

i am the only one who use manager. I still try to find out whats issue but i didn’t change anything, just update software