Understanding bleed for spreads vs pages

[shadowphiar]

I'm doing a magazine-type layout in Affinity Publisher 1.9.2. I understand the requirement for bleed areas around the edge of the printed page, and I can control these in Affinity Designer and place content to the edge of the bleed area, that's fine.

What I'm slightly confused about is the bleed area between two pages of a spread.

The printer asks for a pdf file of all pages (not spreads) - which I am generating with Export PDF (Press Ready), include bleed, All Pages. What I see for example is that on the right hand side of page 2, the PDF includes 3mm of the content from page 3. These pages are going to be printed double-sided as though on A3 and then stapled together - so page 3 isn't going to be printed adjacent to page 2. If anything, I'd have expected content from page 7 to be included (if it is an 8-page document).

Is there a setting somewhere which controls which pages are considered "adjacent" for the purposes of generating content in the bleed area?

Will this not matter? Does content in the bleed area on the inside edge of a spread end up getting removed in software before it ever reaches the page?

bleed.afpub bleed.pdf

[loukash]

The printer will likely use some imposition software which should automatically hide the right-hand side bleed on pages 2/4/6/8 and the left-hand side bleed on 1/3/5/7.

[Old Bruce]

Just for your own peace of mind do an export where you click on the More button and include all the printers marks, you'll see that the strips of colour from the other pages are in the trim area. The other clue is that the pdf is larger than A4.