A10 Envelope Template - why do the frames show on the printed envelope?

I created an A10 envelope template using instructions from this blog. Created the frames as interactive BUT when I go to print the outline of the frame shows. What am I doing wrong? THANKS

You didn’t link “this blog”.
ISO A10 is 26mm x 37 mm. That’s tiny and it’s not an envelope size.
#10 envelope is completely different and only used in a specific region (USA mainly).

Did you go >Insert>Envelope?
What option did you choose in the nexr step?

I cannot reproduce the described bahaviour. Only the print preview is showing a border.