Hello ,
Thank you for contacting us and reporting this problem. In order for us to best troubleshoot the issue you have to submit a bug by following this link here: https://twinmotionhelp.epicgames.com/s/case-community-page which is the button [ contact us ] from the home page of the Twinmotion support community. I have not seen any case come in from you regarding this topic, could you let me know where you sent in the bugs to make sure I can properly follow-up.
The processing error can be caused by many issues that unfortunately is not something you can resolve on your end because it's typically related to how the Cloud hardware and software are communicating with each-other. Which is why we need to investigate those issues to resolve them and having the Twinmotion scene file is important so we can test and find the elements in questions causing problems.
Kind regards,
Vincent B.