It’s not normal and it’s not legal. By that I mean if the Executive Committee thinks it is making “decisions” and instructing the strata manager on the basis of those “decisions”, they are wrong. A decision of the Strata Committee is only valid when it is made by all of the members of the Committee, at a meeting of the Committee, for which proper notice has been given as required by the Act.
As Jimmy points out, the only other valid decisions are those made by the owners in a general meeting.
I suggest you contact the strata manager in writing and advise that it is your understanding that they may be acting on instructions regarding decisions that have not been validly made, and if they continue to do that they may be liable. You should also point out to the Chair and other two “executives” that they are breaching the law.