[VanL]

Here is the analysis: Let's think about the context where this would come up: A party ("Service") takes the SSPL'd MongoDB and implements a service. Service releases some code based on a good faith interpretation of the scope of the release necessary. There is a dispute between MongoDB and Service as to the scope of the necessary code release.

In the ensuing lawsuit, Service raises misuse and argues that the scope is ambiguous. Leaving aside the misuse argument, a court could either a) find for Service, thus restricting the scope of the code to be delivered, or b) find for MongoDB, thus giving rise to an immediate defense of frustration/impracticability, which would undo the contract.

[Bartweiss]

Interesting, thanks very much. I hadn't realized that a new court interpretation of a contract could form the unforeseen circumstance for a defense.