i also get this on expert infos in the columns

Assuming you are seeing lots of duplicate acknowledgements with increasingly high dup ack numbers this means that you were sending out data at a high send rate and an early packet in the window was lost.
Duplicate acks indicate the receiving TCP has seen a packet out of order - either lost or delayed - and the arrival of the 3rd dup_ack triggers a fast retransmission at the sender.
This is not unusual to see and it is not indicative af a severe problem.

Regards Matthias