I'm sure they have a massive to do list, and this is one i'm sure will bubble back up towards the top of priority.
Twitter has shelved a project that would have made it more difficult for the government to intercept users’ private messages without a court order, sources tell The Verge, a sudden reversal for a company that has been ahead of the curve on privacy at a time of creeping surveillance.Report: Twitter Temporarily Shelves Direct Message Encryption [theverge.com]
Twitter declined to comment on why its latest encryption effort has stalled, but all signs point to its overloaded to-do list rather than an abandonment of its values.
This one is still a bit odd... It does give rise to a lot of conjecture that they're holding off on encryption possibly due to outside pressure. It does reinforce for the security conscious that nothing private should be shared on Twitter.