For those that want to know,
conjunction |kənˈjə ng k sh ən|
noun

• an instance of two or more events or things occurring at the same point in time or space : a conjunction of favorable political and economic circumstances.

I'm no lawyer, but I think Webster et al would agree with me that "in conjunction with" does not mean, "occurring near," or "in the same week as," or even "on the day before..."
If your sick trip does not touch one of the specific holidays defined and listed in the CBA, in LBT, it is not "in conjunction with" that holiday (or vacation period) and is therefore not subject to the written note.
Yes, a friend of mine has pressed-to-test this definition with favorable results.