tempo detection of audio shifts midi

Hi all
Apologies if this has been discussed before but I have not found a solution that works for me.

I have a midi arrangement with a fixed bpm and artist decided to add an audio file of live percussion.
The audio file tempo drifts , so I would like to lock the midi to the audio so as to add a little “feel” to the performance.
I ran a tempo detect on the audio and the metronome locks in perfectly…no need to tap for 4 minutes…great
However the pre exisiting midi parts are no longer aligned with grid bars making editing difficult if not impossible.
Moreover If I add a new midi part it aligns just fine.
Tracks are all set to musical mode.
In older cubase I used to tap along to the audio and create a tempo map from the resultant midi track.On turning on resultant tempo track all midi would align correctly.

Evidently I must be missing a step or two
Any input would be really appreciated.

Cubase pro 9.5.3
Win 7

Hi,

The MIDI data should always follow the grid. So once you change the Tempo (make a new tempo map by the detection), the MIDI data should stay (and follow) in the grid. So MIDI data should be in the new time (timecode) but same grid.

Could you share a screenshot of the project, please?

Hi Steve

Will post screenshots when I have access to the machine.

In the meantime while trawling the forums I found this thread that perhaps explains the issue better than I did:

The problem is easy to reproduce.

1.import a midifile of a popular tune making sure it is rigidly quantized…beats are exactly snapped to grid lines
2.import audio of same tune
3.align audio and midi so that first beat is synced but tempo is not perfectly matched, they will drift as the tune progresses
4.run tempo detect on audiofile
5.midi is now not snapping to grid bar lines
6.create a new midi track…events on this track will be displayed and snap correctly

Hope that clarifies somewhat the issue.

Thanks in advance