Which symbol are you looking at? The entire formula is simply Outside()?
There are some known issues with those functions, but this is not one I have seen. For example, you could have an Outside Day occur, and the following bar might not be outside the previous bar, but it might still be outside the first bar that triggered the outside day, so it will show this as an outside day.
In the attached image, bar 2 is Outside Bar 1. Bar 3 is NOT outside bar 2, but it is still Outside bar 1, so bar 3 is still considered an outside day. I believe this is by design, as described in the "reaction day" or rally.
I should point out that if you'd prefer to look only at the prior bar, such could be written simply as a custom formula:
H > Ref(H,-1) AND L < Ref(L,-1)