[I can't set a block]

I'm trying to create a block regen area with this code but it will not set the block.

Note that I have tested that it does work by putting test statements throughout and it seems to just skip over the set block command.

There are also no errors according to the /sk reload command and the logs.

on break:
  if block is in the region "regen":
    wait 10 seconds
    set block at location to block