TypeError: strcasecmp(): Argument #1 ($string1) must be of type string, array given in strcasecmp()

#2 worked for me thnx. Not sure how to track down which module is causing it as suggested by @poker10

In the system.install file, the Unicode requirements are merged into the $requirements array using the system_requirements function:

$requirements = array_merge($requirements, unicode_requirements());

However, when the system status page is loaded, the module_invoke_all function is invoked. This function attempts to merge the requirements recursively. Since the Unicode requirements are processed twice, it results in nested arrays being created due to the recursive merge.
Solution:
We can overlap keys to overwrite previous values (instead of merging them), using array_merge instead of array_merge_recursive.