You mention that you have the latest, but what release is it? Click the top-left menu, then HELP | ABOUT. Does it list "64-bit"?
Unable to replicate the issue here; it's working just as intended. To help solve the issue take a few minutes to share the project. Indicate, by time, where you are making the dissolves.
Sharing is easy, quick and can be done privately. Just follow these steps. Don't skip any, and don't forget, if using Google Drive for the upload, to change "restricted" to "anyone with link can view."
Back up --- 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.
Upload --- Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER. No need to upload the individual VPJ or export file.
Get link --- Right-click the file and click SHARE. If using Google, right-click the file, click SHARE | SHARE. Change "restricted" to "anyone ... can view"
Share --- Click COPY LINK or OK | DONE. Paste that link here, or click the folder at the top-right of this forum to message it privately. 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.