#43738 (comment)

This might be the designed behavior, if we assume a minimum width for a column in the new Articles module. But to be honest, I didn't check the code.
If you set Cassiopeia to a fluid layout and use a large viewport, the configured 3 or 4 columns are in fact displayed.

yes it is the designed behaviour even if it is confusing and not documented

It would be best, when the field "Max. Number of Columns" would be deactived if the Template - Layout ist set to static.
There should be a hint in the inline help which explains the dependencies between layout type in the template options and columns in the module.

From usabilty point of view this is not sufficient. Not self-explaining. If a user changes the template layout to fluid for mod_articles he can destroy his site.
Can we find a solution without grid?

@paternax

It would be best, when the field "Max. Number of Columns" would be deactived if the Template - Layout ist set to static. There should be a hint in the inline help which explains the dependencies between layout type in the template options and columns in the module.

Why would you want to deactivate the field for a static layout? I don't see a reasonable argument for that.
The bigger issue is the lack of inline help, describing the different options and their interferences,

The bigger issue is the lack of inline help, describing the different options and their interferences,

No the bigger issue is that it doesnt work how you would expect it to work. If you have to write an explanation of why something doesnt work then you are just proving that the code is wrong

My comment wasn't about bad functionality. I like the new module with its multipurpose approach.

It is always difficult to take all possibilities into account. That is why I named the field "Max. number of columns", it would be not more than 3, but it can be less ;-) If someone has a better solution, please let me know.
A documentation of the module is in work.

https://docs.joomla.org/Help5.x:Site_Modules:_Articles