As it looks like you are using the OOTB SharePoint form, I presume that the "Content Type" column in the List settings for your workflow list must be visible. If you go to list settings and the Content Type, do you see the Content Type column listed against your Content Type? Default behaviour is that this column shouldn't appear and as such it doesn't tend to appear in the "List Settings" screen, but perhpas yours is? In which case, if it is, you should be able to change it's setting to "Hidden".

If the column is not available to you, you could use Nintex or Infopath to edit the form and remove the Content Type column if it happened to appear on those forms too.

Let me know if any of this helps.

Hello Ryan,

Thanks for your reply, unfortunately the "Content Type" column is still hidden in my task list, and the task is generated by Nintex workflow "Assign Flexi Task" action, I can't directly customize the form using NIntex form.

I also tried to customized the task using Nintex form in the workflow action, but the task is still displaying the OOTB one with content type enabled.

That doesn't sound right. Have you tried creating a new workflow tasks list and seeing if the issue repeats itself there?

If you open your site using Windows Explorer (map a network drive from "My Computer" and map it to the root of your site, then navigate to Workflow Tasks) are you able to see your form that you published (you should be able to identify it by the modified date)?

Hello Ryan,

Even I am facing the same issue. Were you able to resolve it? Please let me know.

Thanks.