While working diligently on the new, Day One 2 compatible version of GiftttDy, I discovered a fix for the rendering problem.
In case you weren’t paying attention, something changed recently where GiftttDy entries did not display correctly unless you manually edited and saved the entry. I originally thought this had something to do with GiftttDy saving to Day One Classic, but it turns out there is a problem with the way AppleScript starts a new line. By forcing new lines to be written using a line feed code instead of a carriage return code, the problem is gone.
Rather than making you wait for the major update coming soon, I put this fix into the current version. If you are already running GiftttDy, just drag the GiftttDy script into your Applications folder. No need to rerun the Configurator.