Issue:
Magento 2 Pre Order was working well until we found out that it is not compatible with Cart2Quote. We couldn't view the Quotation of module Cart2Quote in the admin.
Solution:
Pre Order module and Cart2Quote module both use the same block
Magento\Sales\Block\Adminhtml\Items\Column\DefaultColumn
which causes a conflict between them.
To solve this conflict, we have changed this file app/code/Bss/PreOrder/Plugin/BackendNotice.php
Please check and apply this fixed file on your site.
If you have any issues, please feel free to contact us.
We'd like to help.