Unknown char V message when converting from pdf to pdfa

I have a 2 page document which I am trying to convert from pdf to pdf-a using the following code.

try (final Document pdfDocument = new Document(inputFile.getAbsolutePath())) {
    pdfDocument.convert(xmlPath + "/log.xml", PdfFormat.PDF_A_1A, ConvertErrorAction.Delete);
    pdfDocument.save(outputFile.getAbsolutePath());
}

The conversion fails with the following error.

com.aspose.pdf.internal.ms.System.l5v: Unknown char: V
	at com.aspose.pdf.internal.l159if.le.lI(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.internal.l159if.le.lI(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.internal.l159if.le.lI(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.internal.ms.System.l4l.lI(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.internal.l10if.l0p.lb(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.internal.l2t.l0p.ld(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.DocumentInfo.<init>(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.ADocument.l1n(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.ADocument.lI(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.ADocument.<init>(Unknown Source) ~[application.jar:?]
	at com.aspose.pdf.Document.<init>(Unknown Source) ~[application.jar:?]
	at org.package.application.pdftransform.AsposePDFTransformer.ConvertPDFToPDFa1a(AsposePDFTransformer.java:18) ~[application.jar:?]
	at org.package.application.pdftransform.AlfrescoPDFConvert.importSingleFile(AlfrescoPDFConvert.java:177) ~[application.jar:?]
	at org.package.application.pdftransform.NodeRefFileProcessor.importSingleFile(NodeRefFileProcessor.java:237) [application.jar:?]
	at org.package.application.pdftransform.NodeRefFileProcessor.processFileList(NodeRefFileProcessor.java:142) [application.jar:?]
	at org.package.application.Monitor.importFileList(Monitor.java:116) [application.jar:?]
	at org.package.application.Monitor.processFiles(Monitor.java:212) [application.jar:?]
	at org.package.application.Monitor.processTree(Monitor.java:220) [application.jar:?]
	at org.package.application.Monitor.runFileMonitor(Monitor.java:292) [application.jar:?]
	at org.package.application.Monitor.run(Monitor.java:257) [application.jar:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_65]

Is this due to an unknown font or something else? Is there any setting changes I can make to the Document to fix this?

Document details according to adobe reader
PDF-producer: OpenPDF 1.3.28
PDF-version: 1.4 (Acrobat 5.x)
Size: 48,95 kb
Pagesize: 210 x 297 mm
Coded PDF: Yes
Number of pages: 2

I cannot share the document due to it containing confidential information.

@tijntema

We are afraid that we cannot comment further without replicating the issue in our environment. Can you please share your sample PDF for our reference in a private message as shown in the image. We will test the scenario in our environment and address it accordingly. image.png (14.0 KB)

At the moment i cannot provide this. I will close the ticket. If i am able to provide one in the future, i will reopen

@tijntema

Sure, please take your time. You can leave this thread opened and when you can provide sample document, you can post here. We will further proceed to assist you accordingly.

formulier (5) (1).pdf (47.4 KB)

I managed to get a fake document that causes the problem. This should help

@tijntema

We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): PDFJAVA-43067

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.

Thank you for creating the ticket. Is it possible to give an indication on the estimated processing time of the ticket?

@tijntema

We are afraid that we cannot share any ETA at the moment as the ticket is not fully investigated yet. We will analyze and investigate on first come first serve basis and as soon as it is investigated, we will be able to share some updates with you about its resolution. We will let you know once we have some news about its fix ETA. Please spare us some time.

We are sorry for the inconvenience.