I searched a little and didn't have to much to read into it regarding information, please redirect me to the original if applicable.

The world I'm in I have two fully powered beacons, no achievement had come up, afterwards I Jump off of a tower onto slime blocks I get an achievement, try flying through 1x1 space for supersonic twice, and straight down into a 1x1 hole from build hight, no acheivment, afterwards walked a pig off the side of a cliff while riding I receive an achievement.