Additional harvest partially missing at higher planting seed levels

Hello,
when you plant a seed that is at least 5 level below your own planting level, you have a chance to acquire additional materials as harvest.
These additional harvests are things like the items you need for the titles or rare materials (like bison grass).
In the lower level range (at least until lvl 60 planting) you can also get the normal materials as some kind of double harvest from it. So sometimes you get 2x normal harvest + 1x rare harvest from one seed.
In the later planting seeds this concept is nonexistent and you only get title materials or rare materials from the harvest. So the bug I am reporting is that the double harvest of the normal materials is missing at higher planting seed level.

Additional historic information:
The seeds up to lvl 60 (highest at lvl 55) needed 1,5 days originally. When the seeds after lvl 60 were implemented these only needed 1 day.
This leads me to think that different ppl implemented the different seeds (well, nothing surprising here) and the new guy just forgot the double harvest.
Later the lower seeds got changed to 1 day too (maybe just a change of the parameter) so players starting at a later time would not be able to make this connection.