Why are my trims in the main workspace destructive?

Everyone insists this isn't possible, but it's happening to me consistently- please help me understand what I'm doing wrong.

In the main workspace I split an audio region and want to move it. When I resize the original, the waveform is flat and the audio is gone. I used to use Garage Band back in the day, and used do this sort of thing all the time. In GB I could even copy and paste sections and resize the pasted region with audio that was outside the selected section and everything was still there.

I've attached an example where I'm simply splitting a region, trimming it left, and trying to expand the right hand region left to fill it in. The audio is gone.

This is Logic Pro 11.2.2 running on an M3 Pro MacBook Pro.

Thanks for any help you can give me.