Lag time (delay) after reading posts

[mjohn]

I am using Firefox 48.0 and Windows 7.

When browsing the unread content from newest to oldest, and I find a subject I want to read and then click on the blue dot for that subject or the subject title, the posts then appear and read each one until the end of the thread.

HOWEVER THE PROBLEM IS, how do you go back to the contents where the other topics are list so that you can browse until you find a thread of interest WITHOUT WAITING 15-20 SECONDS FOR THE NEW UNREAD TOPICS TO APPEAR AGAIN!

I did not have this problem with the previous version.

Anybody have this problem and is that the way it is or is there a fix. 

It took me over two hours today to browse, read and comment on several days of unread content.

This delay has been a common theme for me ever since the new format.

I do not have problems with other forums or websites.