This is what the Act says:
OWNERS CORPORATIONS ACT 2006 – SECT 47A
Lot owners must not repair, alter or maintain common property or services
(1) This section is subject to section 56 of the Equal Opportunity Act 2010 .
(2) A lot owner must not repair, alter or maintain—
(a) the common property of the owners corporation; or
(b) a service in or relating to a lot that is for the benefit of more than one lot or the common property.
(3) Subsection (2) does not apply if a lot owner has been expressly authorised by the owners corporation to carry out the repairs and maintenance in accordance with section 46 or 47 as an agent of the owners corporation.
Now, unless the strata manager has total control of the scheme through delegated powers, I would say they had no right to authorise the initial “precedent” window replacement or the additional work.
If I were you, I would write your motion to the owners to include a clause that you seek restitution from the strata manager for permitting the “precedent” work to go ahead, but you might find that too inflammatory.