Does not comply with psr-4 autoloading standard

[resostandards]

Does not comply with psr-4 autoloading standard

[danvbe]

Using composer 2.0.12 I got:
Class RESO\RESO located in ./vendor/reso/reso-php/lib/Reso.php does not comply with psr-4 autoloading standard. Skipping.

I have managed to load the classes by adding a separate entry in composer.json, to load RESO classes with classmap:

"autoload": {
        "psr-4": {
            ..... [my original psr-4 config] ....
        },
        "classmap": ["vendor/reso/reso-php/lib/"]
    },

[venom1979]

Same issue here. Same Composer version: 1.10.6.