Uncaught (in promise) undefined

I currently have the same issue described by OP. I tried to implement the fix from #6 but it didnt work. I currently have splide version 4.1.2. installed but also the 4.0 version didnt work.

Does the error cause lightbox fail or any other display issues? Or just harmless errors?

Also try disabling BigPipe for a mo, clear cache!

No lightbox is showing up and Bigpipe is not installed.
Also one click on the image outputs the error twice.

I couldn't reproduce it last time.

If any more info or you could screenshot your formatter form again, so I can narrow down the issue again, that would be helpful. Thanks.

I will see to it this week.

Hi, here is a collage of my settings & the error:

If you have trouble reproducing the error, I could send you the link to the website as PM - even with login if this helps.

Thanks alot for your effort!

Thanks for details.

The unrelated first error is an obvious file permission problem, see more:
https://www.drupal.org/node/244924 →

Be sure to correct the rest of permissions recursively.

If that doesn't fix it, I will see if I can reproduce it.

Try opening each file on the errors in the browsers, if you can't see them, likely 403 or 404.

OK, no errors are left beside the one reported: Uncaught (in promise) undefined. (thanks for the tip regarding the permissions)

A friendly housekeeping before a new release.

Assumed fixed in the last release.

Feel free to re-open if still an issue.
Thanks.

Automatically closed - issue fixed for 2 weeks with no activity.