Dragging out midi part blank space changes timing

I’m using Cubase Studio 4 on a Mac and I have an issue where dragging out the blank space at the start of a midi block to the left causes the timing of the performance to change (using normal size not move contents or time stretch) on playback of VST instrument tracks.

The midi notes stay in the exact same location yet somehow the timing has shifted, noticeable lag dragging out the start of block to the left a few bars and forward sounding when closer to the starting note, in relation to the other tracks. I’m using a large buffer for the playback of the VST instruments (1024), I thought that this would be okay since I record with an external synth and monitor my performances real-time, then part out the midi from that to the soft synths.

Perhaps using a small buffer and freezing each instrument will help but I’m trying to understand why it behaves like this. :question:

Make sure the pointer tool is the correct flavor.

I’m sure that it is the right tool. The midi notes have the same position values as before.