I am not aware of the Panama Canal being defined as Concession infrastructure in the treaty when Panama agreed to sell the land to America, when America built the Panama Canal.
Nor am I aware of any agreed upon time period in the initial treaty, that said America would give/trade over to Panama the Canal.
Even the later treaty under Carter had 'conditions, that allowed America the ability to intervene.
"Under this treaty, the U.S. retained the permanent right to defend the canal from any threat that might interfere with its continued neutral service to ships of all nations. "
Is something 'truly a nations own property,
When one sets laws allowing foreign nations to intervene should they disagree with your use of it?
If it were 'truly Panama's canal, they could refuse American ships access, though they might face economic sanctions,
'But by the treaty agreed, America could invade, 'if the treaty is ever broken. I assume.