When teleporting an entity with /tp with relative coordinates, the accuracy of the destination seems to vary depending on the entity's previous coordinates. Sometimes it is slightly negative, sometimes it is slightly positive.

This may seem like a well-known floating point error, but it differs in that the coordinates of the destination are always the same double/float value. i.e. Running two commands with exactly the same destination position coordinates(double) teleports to different position coordinates(double).

This only occurs in relative and local coordinates. Absolute coordinates seem safe.

/forceload add 0 0
/summon marker 0.0 0.0 0.0 {UUID:[I;0,0,0,0]}

Case 1 : teleport from 4.0 to 1.1 → 1.1 Expected

/tp 0-0-0-0-0 4.0 0.0 0.0
/execute positioned 1.1 0.0 0.0 run tp 0-0-0-0-0 ~ 0.0 0.0
/data get entity 0-0-0-0-0 Pos

Case 2 : teleport from 16.0 to 1.1 → 1.0999999999999996 Wrong position

/tp 0-0-0-0-0 16.0 0.0 0.0
/execute positioned 1.1 0.0 0.0 run tp 0-0-0-0-0 ~ 0.0 0.0
/data get entity 0-0-0-0-0 Pos

Case 3 : teleport from 32.0 to 1.1 → 1.1000000000000014 Wrong position

/tp 0-0-0-0-0 32.0 0.0 0.0
/execute positioned 1.1 0.0 0.0 run tp 0-0-0-0-0 ~ 0.0 0.0
/data get entity 0-0-0-0-0 Pos

The same problem occurs with the rotation argument of /tp. (Not in /rotate.)

Case 4 : rotate from 2.0 to 1.1 → 1.1 Expected

/tp 0-0-0-0-0 0.0 0.0 0.0 2.0 0.0
/execute rotated 1.1 0.0 run tp 0-0-0-0-0 0.0 0.0 0.0 ~ 0.0
/data get entity 0-0-0-0-0 Rotation

Case 5 : rotate from 8.0 to 1.1 → 1.0999999 Wrong rotation

/tp 0-0-0-0-0 0.0 0.0 0.0 8.0 0.0
/execute rotated 1.1 0.0 run tp 0-0-0-0-0 0.0 0.0 0.0 ~ 0.0
/data get entity 0-0-0-0-0 Rotation

Case 6 : rotate from 16.0 to 1.1 → 1.1000004 Wrong rotation

/tp 0-0-0-0-0 0.0 0.0 0.0 16.0 0.0
/execute rotated 1.1 0.0 run tp 0-0-0-0-0 0.0 0.0 0.0 ~ 0.0
/data get entity 0-0-0-0-0 Rotation