Large? (~88k lines) json edits not saving

[insomniak90]

Using v2.9.0 via Chrome v66 64bit... Same with IE v11... (Chrome seems to respond quicker than IE) Connected successfully to my portal and able view webmap json data. Attempted several json edits and here is what I'm seeing...

• ~88k lines copy json feature does not work, need to pick edit, select all, copy then paste into notepad++
• ~50 lines copy json feature works
• ~88k lines copy/paste from notepad++, verifies but does not save. save gear icon keeps rotating. NO change to the webmap file
• ~88k lines within the UI is laggy, verifies but does not save. save gear icon keeps rotating. NO change to the webmap file
• ~50 lines modified one attribute value within the UI, verifies and saves. change in webmap file
• ~50 lines deleted (empty data) within the UI, verifies and saves. NO change in webmap file

My colleague pointed me to the portal webmap files stored on the server (/arcgisportal/content/items/) and I'm able to modify the json there and the webmaps reflect the changes. This can be a workaround for now but would be nice to have it functioning in AGO Assistant again.

Puzzling thing was that I was able to do a full copy/paste about 2 weeks ago. The only change I'm aware of is that our admin changed our login process from ArcGIS account to our enterprise AD single sign on.

[insomniak90]

I ran Chrome Developer Tools and upon saving edits on the ~88k json this error appeared