last() and [] operator give different results

[Martin Ennemoser]

I have a model RSSFeed. To get the last element in my DB, I do:

RSSFeed.objects.last()
# Output: <RSSFeed: www.sooperarticles.com>

I slice it to get the first 10 element in the query

first_ten_feeds = RSSFeed.objects.all()[:10]

Using first and the bracket operator is consistent:

first_ten_feeds.first()
# Output: <RSSFeed: pressetext News>
first_ten_feeds[0]
# Output: <RSSFeed: pressetext News>

But using last and the bracket operator is not consistent:

first_ten_feeds[9]
# Output: <RSSFeed: FinanzNachrichten.de: Nachrichten zu IT-Dienstleistungen>

first_ten_feeds.last()
# Output: <RSSFeed: www.sooperarticles.com>

Why? I expect to get the same result for last() and [] above.

RSSFeed.objects.last() and first_ten_feeds.last() seem to give the same result but that does not make sense to me.

I already openend a SO question with the same content: ​https://stackoverflow.com/questions/54477472/last-and-operator-give-different-results
There I was suggested to open a bug.