The original piece goes from C Major to D♭ Major, then to D Major, and then to E♭ Major.
When I retuned those to 19edo, it didn't sound too different. The chords sounded like slightly different quality, but not too much.
Since C♯ and D♭ are different notes in 19edo, I tried interpolating between C Major part and D♭ Major part with C♯ Major. And that's where it sounded so exotic. I won't say it's horrible though.
What's the reason? You can listen to the modified version here. (WARNING: tuning doesn't work in mobile version of Musescore.)