Twitter is broken—tweets are missing

Currently the following is displayed prominently at the top of Twitter's I'm Missing Tweets or DMs page:

Bug Alert:

• Some users are not currently able to see all Tweets posted within the past week from accounts they follow. These Tweets might still show up in third-party applications or in your Mentions tab.
• Some users are currently experiencing an issue with direct messages disappearing, without the sender or receiver deleting them from their inbox.
• Some users may experience a delay in DM delivery. A notification may arrive to your email inbox, but the DM won't appear for some time after the email delivery.

Our engineers are hard at work to solve these issues. Follow @Support for updates!

There has been no mention of missing tweets recently on the @Support account, unless those tweets have themselves gone missing *wink*.

Unmentioned in the bug alert are lists.

For the last several hours my Twitter list for Minecraft hasn't been showing all the tweets:

Missing tweets in list @Stratagerm/minecraft (Click to enlarge).

Note the gap between tweets from 2 hours ago and February 16. This list should show dozens or even hundreds of tweets during that time. Notably missing is the tweet made by list member Jens Bergensten 12 hours ago announcing the Minecraft 1.5 pre-release.

I'm not the only user to see this issue with lists but it hasn't been widely reported. I suspect that it is happening more but that people aren't noticing.