Hi Liat,
It turns out that the default for -1tindex depends on the type
of dataset, and is not necessarily 1. There is a -verb option
that you can add, which will output the sub-brick actually used.
Since you used -1tindex for one command but not the other, the
sub-bricks ended up being different.
I will look into making a change for this. But I suggest that
in the future you specify exactly what sub-brick you want to
use for each purpose (unless the input has only 1). These are
_very_ old programs and options (relatively) that relied on
datasets being of certain functional types, which is no longer
the convention.
Sorry for the confusion,
- rick