I don't know why, but the function "isSlimeChunk" on turtle don't work, is always false

Pocket:

Turtle:

computer:

i'm on the same chunk. just 1 block off

A little bit late, sorry for that. But fixed in 0.6.2b

It's possible that you are not in the same chunk as the turtle?
You can see the chunk boarders with F3+G

no, the turtle is on the same chunk

Because this is a more complicated issue than I thought, I will change the milestone to 0.5.3b.