In a given situation, can we assume that a chess engine is tactically perfect - meaning that it can find all possible tactics which are there in that position. Is it possible for the best of modern chess engines to miss a tactic in a given position? Has this ever been observed in any recent game?
EDIT: @Henry Keiter: For the purpose of this question, I would define tactic as a combination or sequence of moves which wins material(if playing the winning side), or a combination or sequence of moves which defends a difficult position successfully (meaning preventing a loss of material which seems imminent). I know that the general definition is broader but for the purpose of this question the meaning can be taken as defined above.
EDIT 2: The reason I am asking this question is I am actually curious if a chess engine really does find all the possible tactics in a given position, or if it just manages to find many more tactics than a human being would find.