If VP is working well for you there's no mandate to update. Allow time for glitches to be discovered. New unlicensed versions can be test driven, and the old reinstalled.
What version is being used? What is the resolution of the bulk of source files? What are the export settings?
The best way to track down issues is to share your project. Someone here will check it out. It's easy and quick; just follow these four steps...
1. With your project on the timeline, click on MENU at the top-left. Click FILE|BACK UP PROJECT FILES TO FOLDER. Choose a folder and SELECT FOLDER.
2. Locate the saved, numbered folder. No need to upload the export or VPJ files. Upload it to a free server - Google Drive, MS OneDrive, etc.*
3. Get a shared, public link. If using Google Drive click GET SHAREABLE LINK. Change "restricted" to "anyone with the link can view" Then click COPY LINK | DONE.
4. Paste that link here, or click the folder at the top-right of this forum and privately message it to me. It won't be shared.
* Before uploading, right-click the folder, click PROPERTIES. Look at the File Size to confirm that it's not too big for the free space on the server.