I ran into this a couple of times.
I have a table, then I filter rows based on date and time. The output table spec of the Date&Time-based Row Filter node has the same lower and upper bound values as the original table (from one step before), even though the rows with these lower and upper values aren’t present in the filtered table.
The same happens when using the Extract Table Spec node after the Date&Time-based Row Filter node.
This looks like a bug to me.