component.find('auraId') method returns an array when only one component with matching ID is found during subsequent loads of the model

Always validate the return type of the method component.find('auraId') i.e. and proceed with business logic 

Example:

const cmps = component.find("auraId’");

if (!cmps) return;

if ($A.util.isArray(cmps)) {

    cmps.forEach(cmp => {

        // business logic

    })

} else {

    // business logic

}

In Nutshell, update the controller logic to handle both a single component reference and an array result from component.find. Use $A.util.isArray on the result, iterate from the end of the array, select the instance that is valid and rendered, and only then access value.