I didn't find that misleading.

"[The memory parameter] is an upper limit on the amount of memory that Tie::File will consume at any time while managing the file" is a false statement. Tie::File's memory usage is unbouded. The docs do specify an exception, but it's very misleading.

The memory value is not an absolute or exact limit on the memory used. Tie::File objects contains some structures besides the read cache and the deferred write buffer, whose sizes are not charged against memory.

Does that give the impression that Tie::File's memory usage is unbounded? If not, then the docs are misleading.