MH-60 Baro Hold leads to hover

Hi,
it seems I'm doing something wrong: I engage the AFSC and the Press Baro Hold and put the Collective to zero. The collective moves as expected and keeps the altitude, but the aircraft begins to slow down slowly until we are almost in a hover. From 100 knots to almost zero, it takes about 5 minutes. This happens with the Trim button lit. Is this the normal behaviour? I have set extremity dead zones, and at least I cannot see any conflicting bindings.
Thanks
Gunter