File sizes out of whack since upgrade to SU2021

Since upgrading to Sketchup 2021, I see my file sizes are 20 times larger. Even if I delete everything including hidden geometry and save the file the file size remains the same.

My fix was to select everything, cut it, open a new file, paste it and then resave. File size back down to normal
File size 18,180KB
File size after cutting and pasting the identical elements

Is this a bug or a I missing a setting in the upgrade?

Are you purging unused components, materials, styles, etc. from the model after deleting? If not, simply deleting from the model space doesn’t get rid of everything.

Of course they you are only copying over the stuff still in the model space and not the In Model but unused components or materials and of course styles don’t get copied from one model to the other.