Link to Approval Task on Mobile Phone does not open Approval form but edit for of task

Dear Community,

we are struggling with a problem with the link to the approval task in a task notification.
We see that user who click the link to the approval task on their mobile phone are 'redirected' to the editform of the task instead of opening the Approval task Form. There is no possiblity to approve the task(s).

We are using Nintex Workflow for SharePoint 2013  ( not using Nintex Forms! ).
On normal desktops the links to the approval tasks are working as expected, so users now always have to login to their desktop to get the tasks approved.

I already had a look on the forum, but changing the order of contenttypes and default contentype in the Workflow Tasks library, did not solve the issue.

https://community.nintex.com/t5/Nintex-for-Office-365/Issues-Opening-a-Nintex-Workflow-Task-Form-in-Mobile-Web-View-or/td-p/24596

Neither did changing the approval url:

https://community.nintex.com/t5/Technical-Issues/SharePoint-Task-form-appears-in-Mobile-browser-instead-of-a/ta-p/89573?advanced=false&collapse_discussion=true&filter=location&location=category:Knowledge_Base&q=approval%20task%20mobile&search_type=thread

Anyone who has a solution / workaround that works?