Fatal error on creditmemo mail grouped product

[arnoudhgz]

Preconditions

1. Magento 2.3.3
2. Production mode and development mode

Steps to reproduce (*)

1. Install Magento 2.3.3 with sample data
2. Add grouped product to cart (Set of Sprite Yoga Straps)
3. Place order
4. Login in admin section
5. Create invoice for order
6. Create credit memo for order
7. In the credit memo section click 'Send Email'

Expected result (*)

1. Mail is send
2. No Fatal Error

Actual result (*)

1. Mail is not send
2. Fatal Error is thrown
   

Fatal error: Uncaught TypeError: 
Argument 1 passed to Magento\Sales\Block\Order\Email\Items\Order\DefaultOrder::getItemPrice() must be an instance of Magento\Sales\Model\Order\Item, 
instance of Magento\Sales\Model\Order\Creditmemo\Item given, 
called in /www/magento233/vendor/magento/module-sales/view/frontend/templates/email/items/creditmemo/default.phtml 
on line 32 and defined in /www/magento233/vendor/magento/module-sales/Block/Order/Email/Items/Order/DefaultOrder.php:99 
Stack trace: 
#0 /www/magento233/vendor/magento/module-sales/view/frontend/templates/email/items/creditmemo/default.phtml(32): Magento\Sales\Block\Order\Email\Items\Order\DefaultOrder->getItemPrice(Object(Magento\Sales\Model\Order\Creditmemo\Item)) 
#1 /www/magento233/vendor/magento/framework/View/TemplateEngine/Php.php(59): include('/ww...') 
#2 /www/magento233/vendor/magento/framework/View/Element/Template.php(271): Magento\Framework\View\TemplateEngine\Php->render(Object(Magento\Gro in /www/magento233/vendor/magento/module-sales/Block/Order/Email/Items/Order/DefaultOrder.php on line 99

When async email is enabled

report.CRITICAL: Error when running a cron job 
{"exception":
"[object] (RuntimeException(code: 0): Error when running a cron job at /www/magento233/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php:330, 
TypeError(code: 0): 
Argument 1 passed to Magento\\Sales\\Block\\Order\\Email\\Items\\Order\\DefaultOrder::getItemPrice() must be an instance of Magento\\Sales\\Model\\Order\\Item, 
instance of Magento\\Sales\\Model\\Order\\Creditmemo\\Item given, 
called in /www/magento233/var/view_preprocessed/pub/static/vendor/magento/module-sales/view/frontend/templates/email/items/creditmemo/default.phtml 
on line 1 at /www/magento233/vendor/magento/module-sales/Block/Order/Email/Items/Order/DefaultOrder.php:99)"} []

Bug introduced at #22265
But if you would revert this change, the mail works, but the subtotal is wrong indeed. So I think the accepted PR did some wrong fix.

[m2-assistant]

Hi @arnoudhgz. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

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[AnnaShepa]

@magento give me 2.3-develop instance

[magento-engcom-team]

Hi @AnnaShepa. Thank you for your request. I'm working on Magento 2.3-develop instance for you

[magento-engcom-team]

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