When the blueprint is maxed out, it has the status "The best blueprint for this configuration". Each redraw or upgrade card can increase some parameters and decrease others. Which numbers you get depends only on your luck! So if the range of numbers includes both negative and positive values, there will also be a '0' value. This is perfectly normal.

There is a dependency on your current setup, the same blueprint can have different stats on different setups. Sometimes their advantage can be negated by your setup to 0. Try changing blueprints and see what numbers you get.