Just to be clear, the “[sci]” should not be included and I see the same problem as you if I do include it. If the task doesn’t work without the “[sci]”, I think you are seeing a second problem; what processing did you do before gscalibrate, eg. with gsreduce?
ok, now I know!
I combined 5 spectra with scombine task, and the spectra were not gscalibrated.
In other words, some information is missed after the scombine task.
Now I gscalibrated the spectra before combine them and problem solved.
Thank you very much James!