BEFORE can be any edit history step. There are several things that chage the BEFORE settings from Adobe Default Raw settings
1. When uou Import with a Preset, Before includes the Preset Edits
2 If you Read Metadata from File, Before includes the edits read from XMP
3 You manually change Before using the Right-Click menu in History or the Icons/Shortcuts in Before/After View.
One way to reset Before to Adobe Default Raw settings and see it happen is to:
1 Go into Before/After View
2 Apply "Adobe Default" built in Preset
3 Rightclick the "Preset: Adobe Default" History item and chose "Copy History Step Settings to Before"
4 Click the step before the top one in History
4 Right Click and do "Clear History Above this Step"