[Update: If you try to include some special characters in the name of a preset being created or imported via Import Presets, LR 7.3.1 silently fails to create the preset, both on WIndows and Mac. See this post for details:
https://feedback.photoshop.com/photoshop_family/topics/lightroom-classic-cc-7-3-bug-not-saving-new-p...
-- John R. Ellis]
If I save a new preset and I use a "|" symbol in the name it disappears. I only noticed this because I was making presets using the "|" as a separator. It worked fine before the update. It does not work now. For example, I have a preset I made called "SPLIT | Heavy Blue". The ones I made before the update work fine (thankfully). But now if I make a preset called "SPLIT | Heavy Green" it disappears. I immediately try again, same settings only changing the name to "SPLIT - Heavy Green" and it saves fine. Loads fine. Works fine.
Weird.
I'm not too upset. It's not a big deal. But it took me a couple hours to figure out what was going on and if it's not a big deal to patch it, then I thought someone should know. I use Windows 10.