Hi Micdt, see my answer in post https://wordpress.org/support/topic/post-masonry-block-not-working-after-update-to-2-0-2/#post-15936456
I will copy the main answer here:
I resolved the issue myself, I guess. Looking at the error, it striked me that the path to the ‘missing’ resource containes a tilde (~) (../wp-content/plugins/ultimate-addons-for-gutenberg/dist/vendors~chunks/post-masonry/react-masonry-component.js). As I do have some programming experience, I thought that this might be the problem. So in the exact same location I added a folder ‘vendors-chunks’ (- instead of ~) and copied the contents of the ‘vendors~chunks’ folder to this folder. I copied the block.js file that calls the file ‘react-masonry-component.js’ in the ‘vendors~chunks’ folder as I could deduce from the second error (as a backup) and I changed the tildes (~) in the block.js file to ‘-‘ (4 cases of vendors~chunks changed to vendors-chunks). I cleared the cache and reloaded the editor page with the Post Masonry block… and all of a sudden it appears! 🙂
This was for version 2.0.2. Hoped it would have been implemented by now, however it is not, so the problems with this Post Masonry block (and others, I guess) reoccurs. I already made a ticket in which I posted the answer to the support team as well. Thumbs up that they will actually do something with my suggestion…