Here's a pic of the two side by side. The older version has a more pronounced point while the new Daytona Parts product uses a blunt ended needle with a reconfigured seat. The new version doesn't seal as well and allows fuel to run by, loading up the carb bowl.
As I mentioned, I swapped the old units back in and it ended the problem.
And for the armchair mechanics, yes, I did reset the float height based on the new design and it did not help. I even replaced the float thinking I'd done something to it - but to no avail. The only fix for me was to reuse the old needle and seat.