Did the body corporate manager follow the correct procedure by delaying a committee vote until an unfinancial member became financial?

The question doesn't say, but from description, it sounds like the vote was held via a VOC.

In that case, the VOC is open 21 days after the date of issue, but it can be considered decided once you have a majority decision. In other words, if you have a committee of seven members and four of them return votes in a way that can decide the matter, the vote can be considered concluded. Once the 21 days have passed, the VOC is concluded, and the votes received should be counted.

However, a committee member cannot vote at a committee meeting or outside a committee meeting if they owe the body corporate a debt at the time of the vote. So, in this case, it seems that only two of the three committee members should have been able to vote.

There is no indication of what happened to member A's vote – did they abstain due to a conflict of interest? If they did, and they formally voted that position, there may have been a quorum, and the motion should have passed. If they didn't, maybe there wasn't a quorum, and the motion could have been defeated due to lack of a quorum.

As a next step, I would go back to the body corporate manager and cite the legislation around counting votes. You can highlight the information on the below page: Committee voting

See what they say. Maybe the decision was incorrect. Maybe you need to have a new vote and have all members vote to get a more definitive position.