Yeah, I had the same issue when I tried to put together an A1 reference. It could not deal with any A1 reference with $AJ (or just AJ) in it. I wound up having to literally hide that column and not use it. I would assume it would also apply to AJA, AJB...BAJ, etc. I am using Office 2016, so hopefully they have fixed this in more contemporary versions. I will note, however Office 2016 is still supported for around 5 more months.