How does enabling background refresh cause preview data to become out of date?

[HamidBee]

I read the following:

https://docs.microsoft.com/en-us/power-bi/guidance/power-query-background-refresh

"Enabling background refresh can result in preview data becoming out of date. If it occurs, the Power Query Editor will notify you with the following warning:"

How does enabling background refresh cause preview data to become out of date?

Thanks for any help.

[lbendlin · Accepted solution]

Background refresh may not catch data changes at the source, and may think that it has the lastest data when in fact it has not. 

I wouldn't worry about this part too much, it is rather irrelevant for your report users.