Elise, according to my current vet, who has 4 huskies under his care, pacing is a common form of separation anxiety. I personally think it's a pretty mild form, and imho, SA can manifest in different forms. For example with Miya as a puppy, it was total destruction. As a 2 year old, it's not eating. I have a thread from a week or two ago, and have pin pointed Miya's lack of appetite to only 2 things, hormones or separation anxiety. Is it cause for concern, maybe. If he's harming himself or things, then yes. If it's simply pacing, then I would monitor him, check on him, let him know you're around. At home he may not be this way, because he is comfortable and has Sadie.
I find it frustrating at times. Since they are so independent in nature, yet do not want to be with out their family. Tonight I worked, first time in four days, and Miya only ate half her food while I was here, and left the rest. Missing it, don't be mad at yourself, like I said, I believe it is a mild form of it. If it helps any, try keeping a journal, doesn't have to be elaborate, but it may be easier for you to see his triggers (as in does he pace every day, or only days you are not around him that much). Also, for me, like today, I did not play with Miya as much as I normally do(cold and rainy today), so I think for her and I, it's about our quality time as much as me feeding her alone vs feeding her when we eat as a family. Keeping a journal, is giving me insight, as well as how I can adjust things to make her happier, and less feeling separated from me.
I hope that helps a little, a lot of this, again for me, has been trial and error.