It sounds like you are comparing Sense Dashboard vs PGE on a day by day basis ? I ask because there were some divergences between the web app (which includes Export) and the phone/tablet possible starting in the August release (maybe earlier). The phone/tablet app was migrated to pulling data from a newer endpoint, while the older legacy endpoint data continues for the web app, Export and informal API. As you can see from this moment in time, the new data endpoint appears to aggrgate/update a little earlier each hour than the older one.
I did a quick comparison for PGE solar net data vs Sense net data (Total Usage + Solar Production) via export for the full 2025 on an hourly basis and things looked pretty good - I see a few bad points, but no real differences between data before and after August. Then again, Export use the old endpoints.
ps: the missing data is from PGE being slow to update data - my data from them only goes through the 14th right now.