Yes, but it’s part of the definition of a light-year, i.e. the distance light travels in a vacuum within one Julian calendar year. Using a year as reference to the distance light travels within a given timeframe is fairly arbitrary. We could just as well use light-months, or light-decades, or some entirely different timeframe as reference.
Year is an incredibly arbitrary length
Years measure time, not distance
Yes, but it’s part of the definition of a light-year, i.e. the distance light travels in a vacuum within one Julian calendar year. Using a year as reference to the distance light travels within a given timeframe is fairly arbitrary. We could just as well use light-months, or light-decades, or some entirely different timeframe as reference.
Speed = Distance over time.
There are no measurements of speed that won’t face that problem.
All lengths are arbitrary.