Scroll in continuous view limited to less than all instruments

Saul A2 - S1 - 8 Sinfonia_2.mscz

Open the attached file
Set zoom to 150% - this is what I was using when I found the problem, setting zoom to whole page allows for a few more staves.
Ensure you are in continuous view (it should already be there)
scroll down to the bottom of the score

Expected: Scroll down to the 41st (staff)
Actual: Scrolling stops at 21st staff - this may vary from one system to the next.

File created using OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.0.0, revision: 26ad655 (alpha release from 9/11/2.18) on Windows 10.

The same thing happens on scores imported from 2.3.2. In version 2.x I was able to scroll down to as many instruments as I added to the score. Checking/Unchecking the Limit scroll area to page borders option in Preferences->Canvas had no effect.