Hi Andrew,
Yes I was planning to do a manual run without that line (and will still do, and I will also try Hugh’s line set, which uses that line but also other different lines) though after looking at Hugh’s errors which are good past that wavelength and mine which deteriorate before then, I now suspect that may not be the problem. I also had a closer look at this line. As I said,it is a triplet and therefore suspect but in Richard Walker’s atlas the 3946.1 line of the triplet is significantly stronger so I doubt the error in that line is more than 1A at most.
Cheers
Robin