For comparison's sake, here's a screenshot from 3.0.0 where it's still working:
For contrast, here was the property when it was under the Musgrave Texture node:
Rotate Euler rotation type inaccessible in bl_rna properties because of name collision
I don't know how hard it'll be to replace under the hood, but maybe renaming the property to something like 'rotation_type' would be more appropriate? That's how it's named under Vector Rotate,…
Rotate Euler rotation type inaccessible in bl_rna properties because of name collision
domain property does not match bl_rna
Store Named Attribute appears to work as expected in 4.0, I don't there is a bug here.
@Suzume-Kraken In your screenshot of 3.6.1, attribute b is 0.000 up to index 7. 
Other programs like Google Sheets use 'Variance' to refer to sample variance (.../n-1) by default, with additional specifiers for population variance (.../n).
The sample variance being the…