I have to tap the post and then reload on mobile, but if it is the last post on a thread or page it won't work. That is why you will see some empty posts for people who want to see what the tweet is.
They are populating on my phone as well. Usually when Tweets don't load, if you physically tap on the link and are 'moved' to Twitter, the initial tweet has been deleted.
When it's the last post on a thread with a tweet, I learned that if I scroll up until I can barely see the beginning of that tweet and THEN reload the page, then that last tweet will load. Sometimes it takes more than one try, but I'm already used to doing this for all tweets all the time.