spacers not working properly

I'm having issues with the function of spacers suddenly in v. 3.6.2
Formerly I could use a spacer to increase the space between just the adjacent staves where I placed the spacer. Now, however, when I add a spacer and drag it, it increases the space between all of the staves equally. This is not what I want! Any tips?
I am sure this is not a page fill issue. I have the page fill threshold set to 0, and the spacing happens incrementally.