Good evening! I was at 19.6 weeks for an ultrasound, and the baby had…

Good evening! I was at 19.6 weeks for an ultrasound, and the baby had a heart valve issue in the left ventricle of the heart measuring 1.6 m and 2.1 m. The sonographer says not to worry, it happens often, it will likely resolve closer to delivery, we'll see on the 30-32 week mark. Has anyone experienced this? What do you know about it?