A few days ago, I updated to TB 60.3.0 for macOS. Today, I noticed that no threaded conversations were visible in my Inbox when scrolled to the newest messages. (I leave the bulk of my email in my Inbox.) This is unusual, as I am on a couple of very active email lists that almost never go more than a day without a threaded conversation. I found that if I unthreaded messages (View > Sort By > Unthreaded), messages that belong to threaded conversations popped up among today's email. I selected one of those messages and turned the threading back on, which revealed that the threads in my Unified Inbox were sorted before the oldest emails in my Inbox. I did some more testing, and determined that this happens only in the Unified Inbox, with messages sorted by Date, viewed as Threaded. Details: • I view my email in the Unified Inbox, sorted newest at the bottom. • My Unified Inbox shows more than 75,000 messages, from a total of nine email accounts. Roughly 70,000 of those messages are in a single IMAP account, hosted by my domain services provider, who grants me nearly unlimited email storage at the service level I subscribe to. • The threaded messages appear sorted to the proper places if I view the Unified Inbox as Unthreaded or Grouped By Sort. • If I view the Inbox for my primary IMAP account by itself, with messages Threaded, the threads properly sort, based on the date & time of the most recent message in the thread. • If I view the Unified Inbox with messages Threaded and Sorted By Date Ascending, the threaded messages appear at the top of the list (the opposite end from where my nonthreaded new emails appear), sorted in reverse by the date & time of the most recent message in the thread. (That is, the thread with the most recently sent message is first in the list.) • Oddity #1: Between the first and second threads in the list appear four old messages in one of my minor accounts. These four are not collectively the oldest messages in my Unified Inbox—there are several from my primary account that are about the same age—but two of them are older than anything else. • Oddity #2: This mis-sorting does not apply to *all* my threads. It applies to only threads whose most recent messages are 2018-05-13, 2:14 pm, or later. Threads whose most recent messages are earlier than that are being sorted correctly. It also applies only to threads in my primary email account—none of the mis-sorted threads are in any of my other email accounts. It also does not apply to all threads in that account—there are a handful of threads in that account which are not mis-sorted in this manner, and I am not readily seeing any differences between the threads matching the other criteria that are correctly sorted and those that are not correctly sorted. • I updated to TB 60.3.1 tonight, in the hopes that it would fix the issue, but it did not change how my Unified Inbox appears. • I have tried restarting TB in Safe Mode, with all add-ons disabled, but the issue remains in Safe Mode. • Finally, I have add-ons version checking disabled, because there are a small number of extensions I depend upon whose developers have not yet certified them as TB 60+ compatible (and may never be so certified). I have experienced no problems with any of the add-ons in question since disabling version checking, and the fact that disabling all add-ons does not affect the problem suggests that my use of these outdated add-ons is not responsible for the issue I'm experiencing, so *please* do not simply tell me that my problem is using outdated add-ons or disabling add-on version checking, unless you can show that this is a known issue related specifically to one of those. My use of outdated add-ons is neither capricious nor reckless, and I Know The Risks. That said, genuine information anyone can provide would be appreciated. I hope that this is just a setting somewhere that I'm overlooking.