OJS3 cannot import xml without authors

I cannot import using Native XML plugin when article in xml file does not have authors. It was possible in OJS2. Could it be made possible in OJS3 too? I get the following error message:

Validation errors:
Element ‘{http://pkp.sfu.ca}submission_file’: This element is not expected. Expected is one of ( {http://pkp.sfu.ca}title, {http://pkp.sfu.ca}prefix, {http://pkp.sfu.ca}subtitle, {http://pkp.sfu.ca}abstract, {http://pkp.sfu.ca}coverage, {http://pkp.sfu.ca}type, {http://pkp.sfu.ca}source, {http://pkp.sfu.ca}rights, {http://pkp.sfu.ca}licenseUrl, {http://pkp.sfu.ca}copyrightHolder ).\n

An example of article which does not have authors - Kasmetinės geologijos krypties doktorantų konferencijos santraukos / Abstracts of Annual Conference of PhD Geology Students | Geologija. Geografija

Another example, I had to use fake author - Dedication to Professor Leonas Valkūnas | Lithuanian Journal of Physics