Traditionally, transition-based parsers were trained to follow a so-called static oracle, which is only defined on the configurations of a canonical computation that generates the gold tree, returning the next transition in said computation.
dynamic oracles are non-deterministic (not limited to one sequence, but supporting all the possible computations leading to the gold tree), and complete (also defined for configurations where the gold tree is unreachable, choosing the transition(s) that lead to a tree with minimum error).