It seems that the traces of the schematic layout are not all 100% correctly interpreted when the schematic is exported to the PCB.
I got many purple lines connecting pads which are not as per the schematic.
I somehow get the feeling that it was caused by moving some traces on the schematic and the resulted in extra nodes created on those tracks - in particular on the straight pieces and on the ends which happened after one have taken some direction changes out. It is as if the nodes are not merged properly when the wire becomes straight.
It seams that this reflects on the PCB in the purple connection lines.