The problem has been there from the very first moment that I had Sooloos equipment, which was the MC200 in april 2012. After that I bought the MD600 and the problem persisted. The Mac has been the same and has had OSX 10.6.6 Mountain Lion on it without changes.
Well, Mountain Lion wasn't released until 25 July 2012, so you can't have had it in April 2012.
And 10.6.6 is Snow Leopard, a version which was current from January-March 2011.
I must correct myself: I think the instability I saw occurred when I installed Mountain Lion, not from the previous Sooloos update itself.