"Mark all as read" doesn't make me read the last message

I don't know if it's supposed to be like this but for example if I read a topic "A" with 15 messages then there are 5 new messages added later on. If I mark "all as read" then click on the topic, I am directly redirected to the last message I read so here the 15th message but shouldn't I be redirect to the 20th message ?

Reproduce the reported flow: read the first 15 messages, add 5 more, use “Mark all as read,” and open the topic. Trace the read-state and topic-navigation entry points involved; done means opening the topic after marking all as read reaches the 20th message, with a regression test for this scenario.

Written by the indexing model from the issue text.