We have tested the scenario and have managed to reproduce the same issue at our side. For the sake of correction, we have logged this problem in our issue tracking system as WORDSNET-18823. You will be notified via this forum thread once this issue is resolved.
We narrowed down the problem. It seems the ASPOSE Lib has difficulties in parsing forms fields.
Here the minimized document with the form field. lightDoc.zip (49.2 KB)
Please use the latest version of Aspose.Words for Java 19.7 to avoid this exception. The exception is not thrown while using Aspose.Words for Java 19.7.