A couple quick notes on things I've tried that did not fix the issue: 1) add_on_products vs. add_on_others: I've long used add-on/add_on_products for these repos and only became aware of add_on_others when I reread this section of the AutoYaST documentation just now. (Apparently add_on_others is new for SLE/Leap 15?) However, this bug happens the same whether I use add_on_products or add_on_others. 2) I tried wrapping one repo's URL in a CDATA block just in case there were some escaping issues, but that also did not affect anything.