Text is going outside of text box and has irregular leading

Whoops, I got that wrong.

This is the vertical offset.  We can't see that in your screenshot, but I suspect it might have something other zero in that field if you click on the three dots (my second screen shot) or use the Character panel.

This is not the first time we have seen people confused by the conextaul nature of the Properties panel.  It doesn't even show a scroll bar when there is hidden content. We have to know that the three dots might reveal more of the panel and other fields.

It might not be about leading. Some other things to check, as shown in the demo below:

In Properties panel, Character options (or the Character panel) look at Baseline Shift.

If those are actually two separate paragraphs, in Properties panel, Paragraph options (or the Paragraph panel) look at the Space Before and Space After paragraph settings.

I’m guessing it’s about paragraph spacing.