SUMMARY Saving assistant set does not preserve color and opacity correctly. It does save a custom color for the first assistant, but not for the second (it resets to default on loading the set). Global color and opacity does not save at all.
Thanks for your report, This doesn't happen in the latest master build for me (git c5838c0), so I am assuming it is fixed. If you try the 4.2 and see this bug still happening, don't hesitate to reopen this report!