handset rings with headset, sometimes

I have a nokia 3650 (with t-mobile if anyone thinks it matters).

When I have a wired headset, the handset continues to ring. When I use my
BT headset, the handset does NOT ring. I cant find any settings that seem
to be specific to this. Any ideas how to get the handset to always ring?

It doesn't appear to be a profile issue. The settings for "hands free" and
"headset" are both set to "Active Profile" and I have the "normal" profile
set before I use either headset, and I have tried to re-select the "normal"
profile after turning on the headset. I've also tried setting everything to
"normal" instead of "Active Profile" and I get the same results.

Am I missing something? Or is this a bug (aka feature)?