SharePoint Design Workflow: Issue with workflow content type

While I was working with a client, we stumbled across this issue.
They have this request to add/modify existing SharePoint designer workflow task form with new fields. Simple change!
But came across these 2 issues and how I solved it.

Issue: Field Update
Update the form fields (As required)

 

No reflection in InfoPath form

Even after force updated from CT, still no success.

To Fix Field updates:
Remove/rename/delete away the form from workflow

Re-update the CT from Workflow which will generate the new form & fix the issue.

Issue: CT Unable to show up in the task form
While updating the task form for the user collection activity, you will see blank & CT updated with no custom fields

To Fix CT not showing in the form:
Proceed with adding back fields, (here you need to know previous fields, you can track back from previous task forms)

Delete away the existing InfoPath form for that CT

Publish the workflow. Will fix the CT & form.