I'm using QCAD Community Edition 3.27.7 on Windows 11.

When I started my drawing, I was able to change the size scale factor of (existing) dimensions using "Edit/Drawing Preferences/Dimension/Dimension Settings/Size scale factor". However, suddenly this feature stopped working and now I cannot switch the dimension scale factor any longer.

I used this feature to be able to adapt the scale factor of the dimensions when printing in different scales.
I.e. all my drawings are in "original" size but when it comes to printing, I print some parts in scale 1:2 (in which case I used to set the size scale factor of the dimensions to 2) and some parts in scale 1:10 (in which case I used to set the scale factor of the dimensions to 10). Using this procedure, the dimensions have the same size (font size, arrow size, gaps etc.) on both drawings.

I have attached the drawing, that shows the described issues.