If I run the btsppEcho midlet (here) on my 7610, and another instance on a second phone (I've tried Moto Razr, 6230i and 6600), then whether the phone is in client or server mode, as soon as the 7610 *receives* a message it will disconnect immediately after. It has no problem sending.
The app works fine between any other two phones I have.
Is this a bug in the 7610 JVM?
I tried this because I am seeing the same behaviour in my own SPP app. As soon as the app receives a blob of data it will not receive any more. The app works fine on any other J2ME phone with JSR-82.