Hello There,
Thanks for reaching out to WPML Support. I will be more than happy to assist you in this matter.
We have already identified the issue you mentioned and are happy to inform you that the issue is solved now. Moreover, an update (version 0.3.0) of the WPForms Multilingual plugin has been released.
In order to see the URL in the Advanced Translation Editor, first of all, make sure that the WPForms Multilingual plugin is updated to its latest version. Upon confirming that, please try the following steps-
1. Go to "WPML > Translations" to find the Form you want to translate and click on "Resign".
2. Next, open the Form you wish to translate in the WPForm editor and make any changes to the confirmation URL (hidden link). Save the changes.
4. Once you take the Form for translation, the Advanced Translation Editor will launch. Within the editor, enter "http" in the "Source" box(hidden link). The confirmation URL you've inserted for your form will appear in the Translation Editor.
You can also check this video for a better understanding: hidden link
I hope you'll be able to successfully translate the URL after that. However, if you require additional assistance, please do not hesitate to inform me, and I will be delighted to assist you.