TCP input does unwanted aggeration / buffering

[julled]

I have the following config for kplex 1.4:

[tcp]
address=192.168.70.250
port=10110
direction=in
nodelay=yes
persist=yes
[udp]
address=127.0.0.1
port=10111
type=unicast
direction=out
coalesce=no

But when i check the output i get rougly 5 Messages at once every seconds:

sudo tcpdump -i any udp port 10111 -A | grep HDT

But when i check the raw connection i get the 5Hz messages directly without any aggregation:

nc 192.168.70.250 10110 | grep HDT

Cchecked the kplex docu but couldnt find a setting which could further reduce the effect.
What could explain this behaviour ? I need the messages without buffering / aggregation.