Query load unable load Excel sheet due to background fill. Is it a bug?

Is there a bug in Power BI whereby cell fill impacts upon its ability import data from Excel?

I discovered the potential bug whilst trying to solve a problem as to why a 512 row by 19 column sheet would never load in Power BI. There was something about the sheet that caused Power BI to consume every available resource when loading the sheet. It took a while to discover the root cause. I tried several things including only accessing the specific columns I needed in the query, trying a different machine and saving the file locally. Nothing would stop Power BI consuming every available resource when loading the sheet. Then I noticed that several columns and rows had a background fill which had been copied down the full height and across the width of the sheet. Removing the fill allowed the sheet to load in seconds. I suspect that what I have discovered is a bug but it also serves to illustrate a way by which you can optimize sheets for processing.

As I cannot easily see away to add images to a post I have presented them here > https://buildbod.com/2019/05/12/beware-the-fill-of-infinite-consumption/