I only looked at one viewport so far. I found that after I added the 1mm:250mm scale as a Custom Scale in my list and attached the leade for the label to the model, the scale was displayed as expected. Do you have the 1:250 scale in your list of scales?
Edit to add: I went through the rest of the viewports on the sheet and connected the leaders to the model geometry. They all show the correct scale now at least for me. Here’s the file.
Dropbox - ATR036V_R05 with scale labels.layout - Simplify your life.