[my bad] Lemmy's backend has this bug : not displaying one post between page one and page two of the feed

update : No. ...because something else happened : there was a single post that did not show (sometimes) on my feed ...but it did show when I open the Community page ... I really don't get it // do not know what is the problem here.

deprecated :
... to be tested if this applies to any two consecutive pages (like when using next and previus buttons)
i.e. : if there is one more post in the feed the last post of the first page should go as the first post of the second page but it falls between two pages instead.