The colors for changes (red for deletions, green for additions) became a dark gray for both

[F_A_R]

So far, the colors for changes have been the expected red for deletions and green for additions.

Upgrading to 3.0 (199) changed both colors to the same dark gray. This happens for both themes (light and dark). Please see the right side of this screen capture:

Any hints?

Thanks.

[F_A_R]

Solved: 

First, I quit Sourcetree. 

Then, I did a deep dive into this file and invested some quality time searching for possible clues:

~/Library/Preferences/com.torusknot.SourceTreeNotMAS.plist

After being satisfied with my observations, I obliterated the XML contents related to all occurrences of this regex:

Colour.*300

I restarted, to settle the system cache dust.

Big sigh of relief.

BTW: This annoying behavior happened under both macOS High Sierra and macOS Mojave.