Not sure, why is this happening… I haven’t forced the default spacing, and I cannot say, when exactly this did happen
Any idea? Is this a bug?
I’ve deselected the option (I translate from Spanish): “automatically solve overlapping between adjacent staves and systems”.
I don’t know what kind of object could induce that behavior…
Sometimes, when I get strange spacings of systems, closing and reopening Dorico brings everything into order again. Did you try that?
I hadn’t thought of that, but thanks, I’ll do it next time! 
Do you have any ossias or extra staves in your arrangement, Miguel? If you see this problem again, please consider zipping up and attaching the project here so I can take a look at it.