That's pretty simple to identify. You have either log-encoded or HLG clips on that sequence, which Premiere will display as HDR (HLG is a form of HDR). You can simply dial them down in a Rec.709 sequence, but the monitor is set to Rec.709 and will limit what it shows dynamically.
But the export will show that the clips are actually HLG.
So ... to fix this, let's do Color Managment 101.
Go to the Project panel.
Select one or more clips with the same issue.
Set the Override-to option at the bottom to Rec.709.
Make sure the sequence CM settings are Rec.709
Make sure you use the 'standard' export presets that DO NOT have HLG in the name.