WAVELAB 11 playback speed up

Hello Folks
If I work in the DAW (Ableton 11), record a wav file, then call WAVELAB 11 inside the DAW to make some changes to this recording, the playback starts in the right tempo but then changed and speed up. DAW and WAVELAB has the same 48 Khz Samplerate. Please help ! G.Paul

Ok, if i work inside the DAW and edit the wav file with WAVELAB 11, the info is 48000 khz 24 bit, if i change the 48000 khz to 44000 khz for this file in WAVELAB 11, corner right , playback starts to slow, but speed up to the right tempo. What is going on, here. confused ! G.Paul