open links from other programs rotates among windows

In the past, opening a link from another program in the background - e.g., Command-clicking on link in a Mail message - would open the link in a tab in the currently active Safari window. (Yes, "open pages in tabs instead of windows" is set to Automatically, though the behavior is the same if it's set to Always.) Now the first link I click does work that way, but success Command-click's open tabs in other windows. I haven't been able to figure out how it picks these. It's not the or that Command-` traverses them, or the reverse of that. Finding where these new links have opened if you have a bunch of Safari windows open is a pain.

Using open from the command line always seems to pick some random window to open the tab in.

I'm not sure exactly what updates caused this to happen. I'm currently on Safari 18.1 on Sonoma 14.7.1. Safari 18.1 on Ventura 13.7.1 does not exhibit this behavior.