Is this a bug? Trends usage vs device usage


I read where someone else had their usage under trends different than what it shows on the device page, I could t find the thread.
So what is happening under “usage” and a specific device is it shows total KWH for the set timeframe. When you go to the device page the calculation doesn’t match across the two pages.
I figured out why this is for me and my “heat strips”. My heat strips are 15kw, sense detected one leg of 7.5kw and then later the other 7.5kw as another device. I left it this way for awhile then merged them. When we merge, the data is combined for all the history of the merged devices and shows that way on the device page.
On the trends, usage page they are not.
On my device page I only have one device for heat strips but if you look at the usage page you will see 3. It did not combine the history.
Is this a bug?