If the motion was carried and the by-law to be added then you’d probably need to revoke it.
We had an issue where a motion was carried at a agm (in the days when just a few turned up to vote). When it was later discovered it was full of nonsense it needed to come off the same way it went on – at another agm.
The next agm we had a motion and this detailed why it was not valid, not therefore enforceable and potentially put owners at risk of blowback/fix it at all owners cost. If you write the motion and tell your story through the explanatory note you can usually over come others lethargy if they think it might bite them down the track.
So, kill your current situation by a motion (if successfully voted in) then start again, with another motion (maybe/maybe not also at that agm – but do it when it’s good to go), or not.