Updating sprockets to 3.5 caused us to come across this issue:
ActionView::Template::Error (no implicit conversion of Sprockets::Asset into String):
5: font @font_face
6:
7: im = Rails.application.assets.find_asset(Spree::PrintInvoice::Config[:print_invoice_logo_path])
8: image im , :at => [0,720], :scale => logo_scale
Updating sprockets to 3.5 caused us to come across this issue: