I've noticed this issue while testing few components in Lens, which can be quite misleading for the user I think.

This is an example of a UI affected by this:

the first time I saw it I thought the values were invalid somehow, but after the investigation I found it was the Safari correct about the spec. 😓

While by default the fallback value for step is the integer value 1, hence any floating point should be invalid, most browser do not respect this and let the user input any value. Safari is the only browser which implements the invalid check by the spec on this side.

(source: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/number#step )

Safari:

Chrome:

Using the any step value seems to align Safari with the rest of the browsers for the validation.

I'd propose to add a any fallback for the step prop on the EuiFieldNumber component to fix this behaviour.