P: Character leading broken

Agreed. This issue has been a genuine pain. And though I understand that accidents happen to us all, it boggles the mind that Adobe let this one slip through the cracks and land in our laps. 

There is additional conversation going on about this issue on the Photoshop General Discussion forum on Adobe. This bug is a big pain and affecting workflow, but another workaround was mentioned that has worked for me. (Thank you, Ivor) and this might help in the meantime so I will pass it along. If you copy the transformed text into a brand new text box and work with it from there, the leading works and you can scrub with the arrow keys just fine afterwards without having to use the Properties window. I haven't tested it a million different ways, but it seems good so far for me. If you go to the forum mentioned, search for Photoshop CC 2018 line spacing  and you should find the discussion.

Good afternoon,

After upgrading to Adobe Photoshop CC 2018, I have discovered a bug when adjusting "leading" through the Character panel. When I enter a value into the "leading" field, it changes to a value I did not enter. When I try to scrub or use the up/down arrow keys, the value only changes in one direction and with a large jump in value. I have discovered that this occurs after transforming the text layer.

Any advice on how to fix this?

Been a week and still no update to fix this. My whole department is waiting.

If you change the size of type by grabbing the handles of the text box and dragging (with or without SHIFT to constrain things), then you're transforming the text in the same way that you transform an image.

If you change the size of type by entering, selecting, or scrubbing the numeric value of the Font Size, then you are NOT transforming, but rather simply resizing the text.

I updated to Ps CC 2018, and now when I adjust the "leading line spacing", it jumps to extreme numbers when I try to drag the arrow to increase it. It goes up to like 15,000 px on its own and then gives me an error message that it's beyond the maximum spacing. I can't even type in a specific number without it doing the same. Please help me because this is beyond annoying... Thank you!

I'm also using a Mac (macOS Sierra 10.12.6)

what does it mean transforming type?

I like how Adobe leaves comments like this here, even though personally I would find it very hard to believe, but Apple would simply delete this comment, so I think Adobe is getting better again.

Worked like a charm for me, nice work Chris! Other people going back to previous versions, try this quick fix first.

Same issues as the rest.
Adobe Photoshop Version: 19.0 20170929.r.165 2017/09/29: 1138933  x64

It also happens when I try scrubbing back and forth over the leading symbol. Crazy value jumps.