Use the Chase Events function
If you start playback in the middle of a project, some events might not be heard (such as MIDI notes, sustain pedal events, and pitch bend events that start before the point where playback begins). With the Chase Events function, Logic Pro analyzes the project to include some or all of these events when the project plays back.
There is a potential problem when using Chase Events with notes used to trigger a drum loop in a sampler. Unless you start the MIDI region precisely at the beginning of the sample loop, the sample will be triggered at the wrong time and will play out of sync with other regions (at least until the next trigger note). The problem occurs because most samplers can only play samples from the beginning, and can’t synchronize them to the beat when started in the middle.
Set up the Chase Events function
Choose File > Project Settings > MIDI (or use the Open MIDI Project Settings key command), then click Chase.
Select the checkboxes of all events you want to include in project playback.
For more information, see Chase settings.
Avoid triggering sampler drum loops when chasing note events
In the Track inspector, select the No Transpose parameter of your drum loop instrument.
Deselect the In ‘No Transpose’ Instrument Channel Strips option in the Logic Pro > Project Settings > MIDI > Chase pane.
These settings prevent your sampler’s drum loops from playing until they reach the next trigger note, whenever the project jumps to a new position.
The No Transpose parameter actually prevents transposition by the region playback parameters, which is also not desirable for drum sounds or loops.