At the bottom of each product, there is a section called "Product Design Details" where you can set Content Blocks to display. i.e. Design Details 1, Design Details 2, etc...
There are currently 48 content blocks available. When I choose the newest ones that I created, nothing displays. If I change it to an older one, it displays just fine.
When I look at the page using the inspection tools, there simply is no content. The columns are there, just no content. Even if I just put in a single word, nothing.
And again, if I switch to an older one, it magically appears immediately (not a caching issue).
I have compared the content from ones that work and ones that don't and I can't see a single difference. Not even an out of place .
You can try one thing, just delete the older one and use the same identifier for the new one created. Maybe the blocks have been added with a layout which is using old identifiers.
Hope it helps.