Mixer is not being updated after load a custom sound configuration from the score

I've created an orchestra score with 24 instruments. I use Sonatina Symphonic Orchestra, so when I created the score I configured the SFZ on the synthesizer and saved the configuration to score. When I try to reload the configuration from the synthetiser the load of some instruments fail. Some instruments are loaded but some not and I have to reselect them on the mixer to be loaded and played.
What I do to not reselect instrument by instrument is:
1. Open the score
2. Load SFZ from the score on the synthesizer
3. Close the score
4. Open the score again

With this method all sounds are loaded and played. So what I suppose is that the mixer is not being updated after press "Load from score" on the synthesizer.

A related bug was: #30361: Crash when delete the default soundfont after trying to load a custom configuration

MuseScore 2.0 rev. 2d9e135 - Windows 7