Yes, I've got the GMC release installed now.
I've had exactly the same problem with both but am still looking into why this is happening.
To be fair to WA, I get the same problem even if I simply use the FB generated code from their developer centre in terms of the FB Like button creating a 'flashing' pop up window as it calls and uncalls the Like window.
Strange one. Not sure if FB are having issues at the moment, or if its a problem with my sites (I get the same problem on two different domains)