Export normalization changes the rendered file after your mix decisions are made.
Definition
Level adjustment during rendering
Export normalization is a bounce or delivery option that raises or lowers the rendered file to a target peak or loudness value. It is separate from the faders, plugins, and metering inside the session.
Because it happens at export time, it can make the delivered file measure differently from the mix you approved.
Risk
It can hide or create level problems
Peak normalization can make quiet files louder without controlling true peaks. Loudness normalization can change overall level while leaving compression, distortion, and balance unchanged.
If export normalization is enabled accidentally, the rendered master may no longer match the limiter ceiling or loudness target you set in the session.
Workflow
Check the rendered file
Decide whether normalization is part of the delivery spec before export. If it is not required, turn it off and rely on the mix and mastering chain for level control.
After export, meter the final file so integrated loudness and true peak match the intended delivery values.