How can it be avoided? Seemingly, simple search in the search box promises to be helpful. You search for the full book title or for a fragment, and it returns books so that one of them is the result. Or you need to see the full search results list to pick up what you need. However, the marking a book as Read or Reading doesn't add the book to the Your Books list!
This is strange, you have at this portal two lists! One list is the Your Books one (books that you bought in an electronic format or in paper from Amazon), the second is the list in your profile. The latter includes not only the books you have bought at Amazon, but also any books you got through search and marked as Read or Reading (or any other status).
The roles of lists are different too. Being added to the Your Books list is a necessity if you want that a book was visible in Daily Review or in Your Highlights. At the same time, the books list in your profile is your profile's showcase, no more.
Okay, when both lists got synchronized, the happiness takes you. Then you see your highlights, can use Daily Review and your profile is truthful.
There is no right solution at this time on how to speed up the sync. Even issuing the request to support won't help since they reacted only when sync is done. :) As a palliative there can be advised the way to log off from the Kindle.Amazon.com portal and log in back; or use another browser.