Mailmerge to PDF doesn't work since last update.

Thank you

I had a look at your document. It is very slow due to the many pages. Delete all pages except two and save it as an idml file to clean it up internally.

I don’t think you need facing pages for your document. For the data merge to work correctly you only need 2 pages in your document. The first one and the second one with the data merge variable . When you initiate the data merge it should create all the pages you need in a new document and then export them as a PDF

Maybe also take a look at this discussion: https://community.adobe.com/t5/indesign-discussions/mail-merge-in-indesign/td-p/10042434