Hi Florian,
When we made that example in our Documentation for hidden/dynamic fields, as for how you can pull the ACF ( custom field values) from a Page where our Table shortcode is posted;
We just used the free official ACF Plugin which was available at that time. Here is a screenshot from a Test Site we used, it was the ACF free version 6.3.3.

But, now I am checking online, and I am no longer able to find the free official ACF Plugin, there is some notice on their Site. WPEngine claims their original free version of the ACF Plugin was taken over by WP ORG and was renamed.

( The pro version can still be obtained from WPEngine, though)

They do say on another Page, where we can download the latest version that we can keep using the free version :

Now, when I try updating my old version, which was previously developed by WPEngine - now on my Plugins List, it shows it is now owned/developed by WP.ORG.
And they changed that free Plugin name to "Secure Custom Fields" now.

So, If I understood all of this - basically, the free version of the previous ACF has been taken over ( for some reason) from WP Engine to WP Org, and they renamed it to Secure Custom Fields.
If you install it on your WordPress, you will see it as SCF :

I hope that helps.

Just a disclaimer, all of this information is what I just read online - we are not able to confirm any of this nor to provide any details about exact events that took place - For that, you can try reaching out to the Support of the now renamed ( previous ACF/Advanced Custom Fields -  now Secure Custom Fields/SCF) if you wish to try the free Plugin version - 
You can ask them to see if they can shed more light on the matter, and how all that happened.

Or if you wish the pro version from the original WP Engine developers, you can reach out to them on their official Site 'Advanced Custom Fields'.

I hope that helps.

Let me know if you have any additional questions on wpDataTables and any of our functionalities - We are just not able to discuss any details about ACF and why their free Plugin version got changed/renamed like that.

Hello again Florian,

My apology, I just wanted to add - So when it comes to the free version of ACF, you can go to the official ACF Site here : https://www.advancedcustomfields.com/ and download their latest free version, it will come up as ACF on your Plugins list and basically, should work the same way as before.

I am not able to say what are the exact differences between that 'renamed' WP ORG free version "Secure Custom Fields" and the WPEngine's ( original developer's) free version 'Advanced Custom Fields'.

You can read more details from WPEngine on this 'download Page' : https://www.advancedcustomfields.com/blog/installing-and-upgrading-to-the-latest-version-of-acf/.

You can certainly try them both out and decide which one is better for your use-case.

Let me know if you have any additional questions.