Which forum theme are you using?
I'm using the 'Anandtech default style' theme.
I'm not sure what you mean by the "now viewing counter'?
By "now viewing counter" I mean the graphical structure in the top right corner of the screen, on the far right end of the grey bar at the top of the screen that has the Anandtech logo, house icon, FORUMS link, and MEMBERS link at the left end. (This is after you log in.)
If you haven't logged in, then the Anandtech logo and MEMBERS link are not present at the left end of this grey bar and 'log in' and 'sign up' options are available at the far right end of it, that is, at the right of the "now viewing counter".
Moving from left to right, the structure has two up arrows, one atop the other, followed by a single up arrow followed by a number, then a forward slash, then another number then a single down arrow, and finally two down arrows one atop the other.
This graphical structure is meant to show you which message your are viewing out of all the messages currently posted for the thread that you are viewing.
The double up arrows let you move up to the top of the thread, the single up arrow let's you move up one post at a time.
The down arrows work the same way.
I have just checked, and this structure is present in all three of the available themes.
Though, I don't know if the error persists across all themes.
However, in the Anandtech default style when you post a new message for a thread, after the screen refreshes and your new message has been added to the thread, the counter will read X+1 / X where X is the number of all posts for the thread before you posted the new message.
So, if you were viewing a thread that had 7 messages posted to it, and you added a new one, after the screen refreshes and your message has been added, the counter will read 8 / 7.
That is, it says that you are viewing message 8 out of 7.
Obviously, this is an error.
It should read 8 / 8.
If you scroll up the screen, the "now viewing counter" will update the numerator to show you which message from the thread you are viewing.
But the denominator will still incorrectly show the old value from before you posted the new message and changed the total number of messages in the thread.
At this point, if you refresh the screen on your own using the browser, the error will be corrected and the denominator of the ratio is changed to the proper value.
But, the error still stands.