Where do you get these notions?! Of course it was. Do you believe that because the term "perpetual union" was supplanted by "a more perfect union"?
The delegates, whose job was to amend the articles, created an entire new constitution, which many of the states then proceeded to join by seceding from the old union.
One of the features that differentiated the ratification of the Constitution from the AOC was that it called for state delegating committees, not state legislatures to ratify. It is one of the reasons why it took the more reluctant states to ratify. There was no process of secession from the AOC - merely agreement (ratification) of the new charter under the Constitution.
The old union and the new one were not the same, and coexisted simultaneously for some years, as not all the states joined the new union at once (several waited several years before joining and remained during that time under the laws of the confederation).
There was a period where the two governments existed side by side, but for only 10 months - the length of time for the first nine states to ratify the Constitution. At that point the AOC was superseded by the Constitution and the remaining states were in a state of limbo. Rhode Island, the last state to ratify, did so partly because they feared treatment as a hostile foreign government.
The new union was not styled as perpetual.
Where do you get that nonsense?
The states that remained for several years under the old articles after the rest had left that government (leaving an old government system to create a new one is known as secession) were not in a state of "limbo". They simply remained under the old articles. You are trying to make the two unions seem like they were really one in the same but they cannot be since they coexisted.