Hi Eric,  are you referring to the line height spacing, where I mark in red on this screenshot?

Yes, line spacing.  

Understood. Thanks  @Eric S. Heinz

. This has to do with how the signature was copy/pasted in. Our rich text has limited editing text formatting, but will keep text formatting pasted in from other more advanced editors (e.g. Word/ Google Docs).

To reset the line height, you can just delete the line and then press enter, see: 

For some reason, it is still showing the spaces between lines.  I copied the signature from Word directly to Hub.  This only started happing today.