I want to know the answer to the following question:
What is a matter of dispute among linguists regarding the distinction?
All the background I'm provided with is that "One distinctive feature that has caused a great amount of interest among linguists is what is traditionally seen as three degrees of phonemic length: short, long, and "overlong", such that /sɑdɑ/, /sɑˑdɑ/ and /sɑːdɑ/ are distinct.". Is that enough to answer the question?
Answer: no