Right, but specified to what level of specificity? Does any arbitrary level of specificity suffice?

The distinction between "I'm gone, and I'm not gonna tell you how long" and "I will be gone until 1662101265" is not a binary. I can also say "I will be gone until 9/1/2022" or "I will be gone until next week" or even "I will be gone until next month." I would debate whether all of these fit the definition of 'definite,' but they also are simply points along a continuum of specificity. You can be specific up to the second or the day or the week, or any other unit of time. Where do you draw the line between definite and indefinite periods of time?

I realize I may be coming across as making a big fuss over a trivial issue, but if the purpose of an amendment is to require that something be specified, it doesn't make sense to not actually be specific about what needs to be specified.