Hello, on the second ultrasound they said there is a vascular plexus c…

Hello, on the second ultrasound they said there is a vascular plexus cyst of 8.3 mm in the baby. They told me to do an ultrasound in two weeks, the result is 7.3mm. The doctors say that it's normal, usually during pregnancy it passes, but if the baby is born and it doesn't pass, then they will be examining. Has anyone had something like this happen? How quickly did it go away?