Most countries have petty border disputes.
A famous country occupies territory in Cuba where it built a military prison. Cuba claims that the military presence is occupation of territory it rightfully owns. The famous country refuses to leave; it claims it only leases it based on a hundred-year-old document, and sends $4k checks yearly. Cuba denies, and refuses to cash the checks.
Cuba started a war for independence. The US sunk their own ship, the USS Maine to get an excuse to go to war (according to the Northwoods document declassified in 1998). This kicks off the Spanish-American war where Teddy Roosevelt rises to prominence (the perhaps biggest point of note was the butchering of whole villages, mass rapes, and what were essentially concentration camps in the Philippines).
After liberating Cuba, the US government drafted the Platt Amendment as conditions for giving up the Cuban territory they had won from Spain. There were 7 conditions and one of those was the establishment of Guantanamo Bay. Fidel Castro and his chief gestapo butcher Che Guevara overthrow the previous government and then proceed to break most of the other conditions (though it could be argued that the US should have exercised article 3 and prevented the coup).
Cuba later argues that the Vienna convention on treaties overrules the previous agreement, but the Vienna convention is explicitly non-retroactive (and more to the point, agreements due to a war are by their very nature coercive). It could be argued that the US created an excuse for war isn't very savory and most Americans of the time would have opposed involvement if an honest case had been made (I agree with this). If they had not, it's most likely that Cuba would have remained a Spanish colony and that point is immaterial.
International law doesn't leave room for "pettiness" in this case. If the US were trying to pretend the Cuban government didn't exist and was trying to force non-US entities to comply with that non-reality, that go far beyond petty.
https://en.wikipedia.org/wiki/Operation_Northwoods
https://en.wikipedia.org/wiki/Guantanamo_Bay_Naval_Base#Guan...
I saw you made a comment earlier that both countries say "China" on their passports missing the point of this whole conflict.
I think you should spend at least an hour reading about the history of this conflict (not through China's censored Internet).