Please file bugs with more information, specifically steps to reproduce. See Contributing Bug Reports.

Here's my guess at how to reproduce:

• Make an edit to a task description, producing an "X edited the task description. (View Details)" transaction.
• Log out (or open private browser window).
• Load the task while logged out / private, i.e. as a public user.
• Click "View Details" on the transaction.
• Expect details, get login dialog.

I'll now try doing that.

I can't reproduce, those steps work fine for me on this install. I can click "Show Details" on the transaction above while logged out and get a dialog showing the details.

Here's what I get. Note:

• I'm logged out (no profile image in upper right / login icon).
• Link is present.
• Link works fine.

In T9869#146119, @chad wrote:

Please file bugs with more information, specifically steps to reproduce. See Contributing Bug Reports.

I thought I had given enough information, but here are the steps to reproduce:

• While logged out, try to browse to https://phabricator.wikimedia.org/transactions/old/PHID-XACT-PROJ-sunrbbbohnm323i/
• Observe login prompt
• Log in
• Try to browse to it again
• See custom policy details

You need to give us steps we can actually follow in a development environment to reproduce the issue. We can not examine database data, logs, etc, on the WMF install.

I can't examine any of those either, but I can reproduce the bug on what I think is a relatively up-to-date production installation.
If it helps, this URL was linked from https://phabricator.wikimedia.org/project/profile/1090/#17189 (edit policy entry)

I can reproduce the bug on what I think is a relatively up-to-date production installation.

Great! Can you reproduce it on this install? Then you can tell us exactly what you did, and we can examine the database, logs, etc.

I think I made some here: https://secure.phabricator.com/project/profile/1387/ by editing the Custom View Policy and trying to open the transaction in an Incognito window.

Perfect! This should be easy to fix.