I also had this issue (sorry for posting an additional thread). I did a Web-based factory reset, and reconfigured from scratch (I didn't have a LOT changed from the defaults, so it went fairly quickly), plus the option 27=1 full/100 from the builtin IVR (aa2). It's been working fairly well since then. If I restored a config XML made previously, the problem would return. So GV seems to have changed something slightly, just enough to trick the OBi firmware into not working properly. I agree, I also wanted the SSL option, but as of right now, it doesn't work. I also applied the firmware released 15-Mar-2012, but it didn't cause much of a change (although I don't experience any other issues).
Another maybe slightly interesting data point is that calls from VoicePulse would not connect properly or would be reported by voice announcement as being out of service, but using an alternate GV account (with an IPKall number to serve as the termination of the first call initiated from the Web page) seemed to work OK regardless. But then again, I kind of figured that would work "better" because it's Google calling Google :-).