This problem (maybe a bug) is definitely not "REPRODUCIBILITY:
always; no exceptions" as the bug-report suggests.

I'm using 2.5G these days since 3G drains my battery (in about 6 hours), while 2.5G goes for about 24 hours.

i'm using skype, jabber, and msn, and i'm constantly connected to 2.5G.
when i have an incoming call the phone rings, and the data-connection icon in the status bar is changed (marked with a red crossing line over).
when the call ends, data connection resumes..

this of course doesn't happen when i'm connected to 3G then the data connection remains.

my cellphone operator is Cellcom / Israel.