We have a critical issue on our Magento 2.0.6 (the same issue was also on 2.0.4) whereby the custom options section of a product no longer displays the custom options we originally added. In other words, they are missing.
Despite this, the options are displaying on the live website for said product but we are unable to make any changes or add new custom options in the backend.
We have two highly customizable products which have more than 100 custom options in total and we need to make changes urgently but are unable do to so whilst the options are missing in the backend.
Any help on this would be much appreciated.
check if there are any errors are generated on the server or in magento error log when you try to open those options page in admin. You may be exceeding allowed memory limit or php execution time - it just has to be increased in the server settings to fix the issue.
hope this helps.