I came to report the same thing. Funnily enough, I do not have the exact same output (I am 1.12.3). I am not getting the table enclosure and the "separation" comma is after each final element of the table.
{
120,
84,
}
{
267,
132,
}
EDIT: To provide some context on the use case. I originally wanted to run a function real time but it was way too slow so I am just outputing the computation so I can reuse it in a "static" way.