Has anyone seen this error before?

I have an InfoPath form that is published to a content type - it is NOT
published to Forms Server. I have an OOB Approval workflow configured on
the content type. The workflow adds a task to a task list running in the
same site.

When I complete a document and launch the approval workflow, while the
workflow is in progress, I can click on the associated task in the task
list without a problem. The task details page indicates that the
workflow is running, as I would expect.

Then, when I complete the workflow - either by accepting or rejecting it
- I cannot go back to the task in the task list. When I pull up the task
list, the task list indicates all of the columns I would expect - Title,
Assigned To, Task Status, Priority, Due Date, and % Complete.

Next, when I click on the link for the task, it starts to load the task
details page. For a brief instance, I see the same details page, with
the text that says "This workflow task applies to DocumentTitle".

But then, after a second or two, the page is redirected to a Forms
Server error page, which says "There has been an error while loading the
form".

Has anyone seen this error before under circumstances similar to what
I've described? And more importantly, have you been able to resolve it?