The signatures used to be a bit bigger, by default but the staff probably did some re-working and decided smaller ones would be better. I would think it isn't a bug!
I vouch for bigger signatures, though, some are highly detailed and bootiful so I think if possible it would be a great add back. c:
As I recall, they were bigger way before me returning. But, I think they could be a bit bigger- maybe not overly sized like before but just at a good viewable size.