Teleport command offsets are applied incorrectly

Relative teleport commands appear to be measured as relative to the target but applied relative to the context, resulting in unexpected behavior. For example, this function:

tp @s ~5 ~ ~
tp @s ~ ~ ~

Expected behavior: player is not moved at all
Actual behavior: player is moved 5 blocks in the negative X direction

It appears as though the player moves +5X, then the second command tries to put them back to the context position, which is a relative move of -5X from their current position, but it applies that -5X to the context position instead of the player's position, resulting in the player moving from +5X to -5X.

For another example:

tp @s ~ ~ ~5
tp @s ~ ~ ~5

Expected behavior: player is moved 5 blocks in the positive Z direction
Actual behavior: player is not moved at all

Again, it appears that the player moves +5Z, then the second command tries to put them there again, which is a relative move of 0Z from the new position, but it applies that 0Z to the context position, putting the player back where they started.