It sounds like you might be trying to be snarky, as if someone is trying to sweep details under the rug, but just as "the file had its first bit flipped" is more descriptive than "the file is corrupt" but the latter is still a correct description, "unevaluated thunks" is merely a more precise categorization of "space leak", which is itself a subset of "resource leaks", after all.
Yes, I had heard the term "space leak" used in functional language communities but wasn't sure what it meant. Asking around, the definition is commonly given as I did above.
I thought readers here might find that information useful, given that someone might describe a problem similar to the OP's by using the term "space leak".
It sounds like you might be trying to be snarky, as if someone is trying to sweep details under the rug, but just as "the file had its first bit flipped" is more descriptive than "the file is corrupt" but the latter is still a correct description, "unevaluated thunks" is merely a more precise categorization of "space leak", which is itself a subset of "resource leaks", after all.