Issue confirmed.

@dgt41 Do you know what changed here between J3 and J4? Because the code doesn't look that different to me so I suspect a change in another place (modal?)

%27%20+%20document.getElementById(
Well that part should be a number but it's actual javascript. Probably an error in the field modal js

Yep, I figured out that myself ?
The JavaScript is supposed to read the number but it looks like the URL got encoded and thus it breaks.
It's working fine with the same code in J3.

@dgt41 I had a look again and the only difference I found which may be the cause is #15374.
Before, the URL was used as an attribute of the iframe tag. Apparently it worked to have a JS part in that URL.
Now the URL is used in a data-url and the JS part is now broken.

I have no idea how that could be solved but it seems important to fix. From what I saw, #16639 is the same or at least a similar issue.

I have no idea how that could be solved but it seems important to fix.

Of course everything that is currently broken needs to be fixed, but looking at the great picture of J4 this will be fixed when we transition to custom elements for modals (and tabs, accordion, dropdown). All I'm saying is you re right this is broken and needs a fix, but let's wait till we have the UI components in place (in other words let's not waste man hours on this as it will be fixed later on)

I hope my comment makes some sense :)

I'd prefer to have it fixed soon as I already wasted a few hours on it only to find out that it's the same "known" issue. I guess it will be the same fix anyway that needs to be applied for BS modals as it would be for custom elements.

Confirming that the edit button is still broken

One year later and we are still waiting for the panacea of custom elements to fix everything. With only one person working on custom elements we really need to rethink if its an achievable thing to do

This appears to be fixed and related to PR #25001.