Increment Dates in Excel

See attached screenshot.

The dates in Column A do not entirely line with the dates in Column F because the data recorder that spits out data for Column A sometimes will skip a few minutes. I need to increment the date in Column F for however many minutes were skipped in Column A so that the two columns will line up.

Here's what I came up with: =IF(A3=F3, F3, F3+(B3/1440))

This seems to START doing what I want, but it eventually breaks...check out another screenshot:

You can clearly see in the second screenshot that everything is going well right up until G41. I realize that the value in G41 is covered up, but it is displaying "1/1/2018 0:40:00, then it displays that again in G42.

What am I doing wrong here?