Printing issue with attachments in Thunderbird

Dear, At our computer shop, we assist customers with their email, and for this, we always use Thunderbird. However, this week we encountered a problem where printing was not working. Both the printer and the computer are functioning properly. Printing from all other platforms works fine, even when we download the attachments and print them as PDFs. The issue occurs when we open attachments directly in Thunderbird and then click on "Print." The print preview looks correct and shows the expected content, but the printer only produces two blank A4 pages. We also tested the "Print to PDF" option, and that too results in two blank A4 pages being saved. We’re very curious to know how we can resolve this issue or if this might be a small bug in the program? The program is fully up to date, by the way. Kind regards, Mike Papenburg