No sounds when missing Soundfont removed from Synthesizer

Repro steps:
1) Ensure the sonatina symphonic orchestra sound font is not installed.
2) Open Musescore and ensure there are no soundfonts loaded (delete any if present)
3) Open the attached score.
4) Open the Synthesizer, and press "Load from Score".
5) Verify two sound fonts are loaded in the zerberus tab.
6) Start playback of the score.
7) Remove the two added sound fonts.
8) Start playback of the score.

[Expected]
1) At step (4) an error message should displayed, and no sound fonts should be loaded.
2) At step (8) the default sound font should allow playback.

[Actual]
1) The sound font is "loaded" at step (4)
2) No sound is heard at step (8)

The problem may be due to sound fonts being stored with absolute paths in the save file:

C:/Users/Dell/Documents/MuseScore2/Soundfonts/Sonatina Symphonic Orchestra/Percussion - All Percussion.sfz
C:/Users/Dell/Documents/MuseScore2/Soundfonts/Sonatina Symphonic Orchestra/Percussion - Chimes.sfz

References:
* Soundfont: https://musical-artifacts.com/artifacts/81/sonatina-symphonic-orchestra…