[CentOS] Centos 7: printing four copies with Libreoffice prints garbage

I have a Xerox Phaser 3250 printer

It worked perfectly under Centos 6 when I told cups that it was a Xerox Phaser 3150.

It works under Centos 7, too. I can print pdf files from evince and whatnot with no problems, and printing one, two or three copies of a document from libreoffice works as well.

However, if I tell libreoffice to print four copies of a document ("number of copies" =4) then I get garbage printed on the printer; many many pages containing one or two lines of garbage characters.

If I run the spadmin program and tell it to print a test page, it prints fine. Two test pages, fine. Three, also fine. Four test pages, and I get page after page after page of garbage again.

What could the problem be?