Do the following facts create a coincidence?
This is not merely coincidental. Rather this is part of a consistent pattern that colonial powers used with non-European peoples, and that the US later adopted in dealing with Native Americans. The British most likely drafted this treaty, explained it to the Maroons (ex-slaves who could probably not read) as a grant of their hard-fought freedom, then tried to take it back through deceptive clauses and dishonest explanations.
This is best served by an analogy to contracts of adhesion in the United States. One does not agree to the terms in a form contract that are unreasonable. Would a reasonable slave people, having won their freedom with their blood, then agree that the enslavers would nominate their leaders? Would a reasonable slave people, not being able to read and understand the agreement, agree to become a vassal state of the nation which they just repelled with their own bodies? No.
Instead, the British exercised undue influence on the Maroons to get them to agree to a treaty which did not actually express the intent and agreement of the parties. As such, the treaty should be read to grant full sovereignity, as the British proposed, and the Maroons understood and agreed.
In this same vein, it is vital to understand the Maroon agreement as a Maroon.