TypeError at $file['tmp_name'] ($file is a string not array)

[ntd187]

TypeError thrown with message "Cannot access offset of type string on string"

Stacktrace:
#10 TypeError in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\fs\src\FS\File.php:488
#9 Leaf\FS\File:upload in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\fs\src\FS\Storage.php:163
#8 Leaf\FS\Storage:upload in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\app\routes_utils.php:87
#7 Leaf\Core:{closure} in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\leaf\src\Router.php:907
#6 call_user_func_array in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\leaf\src\Router.php:907
#5 Leaf\Router:invoke in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\leaf\src\Router.php:892
#4 Leaf\Router:handle in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\leaf\src\Router.php:840
#3 Leaf\Router:run in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\leaf\src\App.php:392
#2 Leaf\App:run in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\vendor\leafs\mvc-core\src\Core.php:392
#1 Leaf\Core:runApplication in D:\DEV\mysite\api.eff.vn\wp\wp-content\mvc-app\public\index.php:68
#0 require in D:\DEV\mysite\api.eff.vn\index.php:3

[mychidarko]

Can you pls give some context @ntd187