Column width percentage outputs pixel width instead

I run in the same issue. setting column width as percentage is not possible.

I'm running into this as well. I've also tried setting the "Column width" as a CSS selector, but that didn't seem to have any effect.

I have the same problem but it seems like a Masonry API module problem (at least from what I see in the source of the Masonry Views module). Have you also installed Masonry API version 4.0.0? Or do you user Masonry API 3.0.0?

This is a major bug that makes this module completely useless, it should be fixed.