Cannot Add MPA Feed Producer

**Describe the bug**
Sporadically Cannot Add Feed Producer

via UI after the initial feed producer list is created. Also, sometimes when creating the initial list I attempt to add a name and it creates an empty line above. I have to delete the whole list and start again.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to update asset
2. Click on Feed producer
3. Put in valid name, click "Add"
4. a line is added into the list above... but name is not there and its blank.
5. attempt to add name again... "Field requires a valid account" ; or attempt to delete and add again... still blank; same story.
6. attempt to save operation with blank name, operation fails
7. attempt switch node, same behavior

**Expected behavior**
Should be able to add new users to the list, their name should appear above. You should be able to save thereafter.

**Screenshots**
See line #6 is blank:
https://imgur.com/sUJFJC0.png

**Desktop (please complete the following information):**

Linix Mint 19, desktop Bitshares client 191120

**Additional Context**

I am able to update other aspects of the MPA via the UI.
I am able to update the feed producer list via python request to api node.

No source file or test is named. Start by reproducing the issue through the update-asset Feed producer controls and compare the failing UI flow with the working Python API request described in the report. Done means valid feed producer names can be added, displayed without blank rows, and the updated operation saves successfully.

Written by the indexing model from the issue text.