Hi @keys,
from time to time there are questions about the sync command similar to yours. Here is a link to such a discussion, which will probably help: First little diddy
Basically the sync will and can not sync to an event in the past. One way to cope with this in your case is to write your sync in the live_loop line such as
live_loop :loop_chord, sync: :main do
# code goes here ...
end
But I recommend to read the linked thread and the material in the tutorial to understand more fully what actually is going on.
Martin