Is your Ra 162 an "a version"? As in Ra 162a. The a version runs a 47 1/4" sheet front to back while the Ra 162 version runs a 44" sheet.
Many a version machines will show a horizontal streak about 500mm from the back of the sheet regardless of the sheet size.
This is due to the blanket cylinder gap being smaller and more steeply angled. The smaller cylinder gap is what enables a larger sheet.
It is caused by an abrupt shock to the lead edge of the blanket causing a "reflex" that will show up towards the back of the sheet. This can be tamed by a thicker, less stretchy blanket (I've seen 5 ply blankets used) or feathering the packing a little. Make sure the blanket is slighlty over tightened.