Stage order is a preference
A stage's sequence affects scheduling preference. It does not create an implicit Finish-to-Start chain. Add an explicit stage prerequisite when that particular stage must finish first.
A project prerequisite follows the whole job
A project dependency waits for every required stage of the prerequisite project. It continues to include stages added later. Use this when another job needs the whole result, rather than one named intermediate stage.
Edit the project to select whole-project prerequisites. Edit a stage to select its stage prerequisites. Cycles, self-dependencies and references outside your workspace are rejected.
Dependencies carry consequences downstream
If an interruption moves the prerequisite job, the dependent job's earliest feasible release may move too. That does not mean the dependent job's effort increased. See why forecasts move and collaboration.