Synthesizer: Problem with save/load/set buttons

2.0.3 / Win 7/10

Initially reported in Nov 2016: Freelinking: Unknown plugin indicator

1. Load a score which has had synthesizer settings previously saved to it. Press "Load from score" (in the synthesizer) to transfer these settings to the synthesizer.
2. Now close the score and open another score which has had synthesizer settings saved to it.

Expected result: The "Load from score" button should be active when you open the second score.
Actual result: The "Load from score" button" is actually greyed out. You have to press "Load default" to activate it.

There is another issue which appears similar, reported at: //musescore.org/en/node/226591 .