Update:
- I fixed the code with an empirical fix, that should work for reading the file you shared:
Import FieldTrip channel structure: Binarization of grad.tra · brainstorm-tools/brainstorm3@a83914b · GitHub - Since I am not sure why the previous version of the reader does not work on this file, I also opened an issue on the FieldTrip github:
Getting the coil-channel correspondence from grad.tra · Issue #2040 · fieldtrip/fieldtrip · GitHub
Right now, I think you can update Brainstorm and safely link again this file to your database.
I'll post further updates here if any (depending of the answer on the FieldTrip side)