Print Margin Issue with Epson SC-P600

When printing a A4 size image to Epson SC-P600 something weird happens with the image scaling and border sizes. On the LR Pages Setup, paper size is selected for A4, the margins on the template are defined to 3 mm each. On the print the long edge margins are 3 mm, but the short edge margins 12 mm. For testing I did select the hairline from the Print Settings Layout tab. On the print the hairline is cut off from the long edges. On the short edges the hairline is visible at 12 mm border, but the image itself is cut off about 0,5 mm beyond the hairline. Very confusing! It seems to be so that the printer handles the print area as it were a Letter size print - with the hairline border accordingly - even the image would like to be printed as selected on the A4 paper. Unfortunately part of the image is missing from both ends. Furthermore, when using the sheet feeder the image is centered, but with Front Fine Art tray the first short edge is 3 mm and the other about 21 mm (and also a bit shifted towards middle of the printer, loosing the other long edge margin). Any ideas how to fix this issue?

I am using LR on Mac with OS Catalina 10.15.2