OJS Title string from Native XML import not recognized by Crossref plugin

Hello! I just imported a new issue to a journal on our OJS multisite using the Native XML plugin. However, automatic registration of DOIs with the Crossref plugin failed. Manual deposit through the plugin also failed. This is the error text: “Deposit contains title error(s): Title name value is missing from the title element”

I exported the Crossref XML for review, and the tag is empty. This seems like it may be a bug, since the title is present in the imported XML, and also in OJS.

It looks similar to this bug, but I’m uploading articles from the same journal:Crossref submission fails because Plugin expects parameter 1 to be string, array given [OJS] - #2 by dagosalas

I’m using this PHP program to generate my OJS Native XML:

If it’s not a bug, how should I fix the issue? Thanks for your help