Since you have created this module yourself, we will need to thoroughly review the code at the end and check all the functionalities you have implemented. For this, you will need to purchase an hourly package so that we can review it properly.
The path to the code that has the pricing display code is in here \packages\Webkul\Shop\src\Resources\views\products\prices\index.blade.php.
My team and I double checked it and is the same as the one in your github repository. No one has touched it so I cannot understand why this error is occurring.