If i has an Arrow and I have an function like: /execute @e[type=Arrow] ~ ~ ~ /say @e[c=1] the game targets the Arrow like normal.

/execute @e[type=Arrow] ~ ~ ~ /say @e[c=2] targets 2 entities that are not even close to the Arrow. (The command is executed by the server instead of the Arrow)

Seems like relative coordinates doesn't work fine with functions.