As I'm sure you did, I checked through all of the BizTalk 2010 Cumulative Updates (1 thru. 5) and found no mention of this issue. I also found mention of your issue on Sandro Pereira's blog post which appears to be re-hash of the BizTalk Server 2010 Readme (at which point I ask myself where is the value in re-posting this sort of detail...)
I finally checked the MSDN Archive for details of VS QFE fixes around this issue, but no luck.
I think you're next best step is to contact MS and raise a support call - I wouldn't imagine this will be chargeable given that the documentation is clearly lacking.