@lumpysimon you’re welcome!
The ACF documentation still says only one inner block is allowed
and the gutenberg developer guide says the same thing here “Note: A single block can only contain one InnerBlocks component.”
That is confusing though, because it seems like the core columns block does uses multiple innerblocks. I haven’t taken the time to look into how the core columns block handles it – must be something other than innerblocks – worth looking into!
