first off, Mangadex gives you the option to filter out 'H' material from your reading selection, so if I am using that i expect to not have 'H' material shoved in my face.
second off, there are three doujins this artist/author has made that feature characters of a similar description to these two, anyone who WAS interested in seeing 'H' material from this author would have and should have already searched it up, it's not difficult.
third off, there is no break or other pages to show us, readers, that the last page isn't apart of the manga we are reading and squiggles purposely edited the page to show "shounen" and "onee-san" as the names when the characters from the 'H' material have different names as if squiggles WANTS to trick readers into reading that last page as if it was a part of this manga.
fourth off, I didn't report the chapter so I clearly don't care that much, I like 'H' material just like any other breathing human on this planet(clearly I know enough about the doujin squiggles mentions to know they have different character names than the one in this manga), but when I am specifically filtering out 'H' material from my reading material I don't need someone to sneak some in there.