The notification Banner that displays the crafting results is out of sync with the crafting .

You need a cooking speed of around 1 sec.

try running 1000 tea with fine scent  , it goes ok for a bit then it slows down and only reports about 1 in 3 crafts  , it will do this for around 12 crafts then it speeds up as it tries to catch up, then it slows down again and only reports about 1 in 3 crafts again .

This has been happening for around 3 weeks now.

Depending on how many you are cooking it can result in the spam after you have stopped , not 4-5 hrs worth mind you :-)