Asynchronous RFC calls from R/3 to XI - not closing the connection

Dear Experts!

Currently we encountered the following problem:

when executing <b>tRFC calls</b> from R/3 (6.0) to XI (PI 7.0), the <b>connection stays open</b> all the time (in SM58 it says "Transaction executing") and it causes problems. However, the data is transfered correctly (but only once - later on we need to desactivate / activate RFC adapter in XIin order to break the connection).

On XI level, quality of service is EO, asynchronous mode.

The XI config was checked by SAP guy, on R/3 also everything seems to be ok.

Do you have any idea what can be a reason for such a behaviour?

Thx a lot in advance for any help, ideas.

Piotrek