Spatium setting not taken from .mss file upon creating a new score

When choosing a default style by putting my .mss file into Preferences → Score → Style, the Spatium setting is not taken from the .mss file but reverted to the default one (this is very visible as the default Spatium makes the DIN ISO A4 paper size a bit off from 21x29.7 cm; using a Spatium of 1.75 makes the exact values possible).

When, after creating the new score via the wizard, I run Style → Load Style… and apply the same style file again, the Spatium setting is taken, so this is a trivial workaround.