The scaling code still assumed that adjusting the start & end frames would change the playback scale of strips.
This is now solved by recomputing the strip scale based on the other properties.
The scaling behaviour (everything is scaled as a group, relative to the playhead position) remains the same as before.
Pair-programmed with @Nate Rupsis (nrupsis).
This is for Blender 3.4 for sure, and probably also will get back-ported to 3.3-LTS.
Test builds are available at https://builder.blender.org/download/patch/D16643/