RichText field hyperlink not working

[prismic5 (HXM)]

Hi, I'm contacting you for a customer of ours that is having trouble creating content.
The problem is that he is trying to add hyperlink to a rich text content but for some reason he doesn't get the pop-up when highlighting text to add hyperlink.
However it seems to work for me and in the custom type builder it is checked as to be available at the given rich text field that he is trying to use as seen in the examples below:

The pop-up that is missing:

The rich text field that is having trouble

Any idea what could be the problem?

[Ezekiel (Ezekiel Ravidat)]

Hi @prismic5,

Could you ask them to try in different browsers, on incognito mode, and with all plugins/browser extensions removed? Sometimes plugins interact with the page builder UI.

Let me know how that goes!