Appears to be a cold joint.
Likely the pour went higher than the builder anticipated and stopped allowing the concreate to get thumb tight of cured or they stopped the pour altogether due to some unknown reason unknown to us.
Personally, I have never seen a horizontal foundation crack that high from grade or a horizontal foundation crack that so evenly parallels the foundation shelf or footing.
*Note: Even the color of the concrete is different. That would get my attention.
Existing structure. Recommend a licensed foundation specialist with inhouse engineer evalaute the concrete of concrete structures. ASTM C805: Rebound Hammer For Concrete Strength.
New structure: Ask the builder for any slump test results and PSI records.