My site is white listed and was showing twitter cards/summary of my posts expanded in the timeline for ever. Then I just noticed that they are no longer expanded by default for the past few weeks.
They pass the validator as well.
Here is one tweet that is not expanding:
And here is the URL that should be expanded in the tweet:
And my twitter account: twitter.com/underground_net
My old tweets from my site going back a month are expanded.
Here is one of my tweets from a month back that is auto expanded: (on the twitter timeline, not here obviously)
Did twitter change something? Or did something happen to my account?