Properties Pane on Modern Task Lists broken

Brass Contributor

So I'm experiencing an issue on a tenant where the properties pane for items in Task Lists, in the Modern Experience are showing an error (See screenshot below).


Upon further inspection it seems that there is a 500 Internal Server Error on the call that tries to get the items properties with the following call: https://<tenant><site>/_api/web/GetList(@v1)/RenderExtendedListFormData(itemId=43,formId='editform',mode='2',options=15,cutoffVersion=0)?@v1='/sites/<site>/Lists/<list>'

(I've replaced the actual name of things in the above for privacy reasons.)

This all seems normal and it's only task lists affected. If anyone knows what's happening here, your feedback would be much appreciated

2018-06-26 16_01_59-Matter Tracking - TestTasks - All Tasks - Firefox Developer Edition.png

8 Replies
I didn't think task lists supported modern UI yet?
Agree with Chris...last lists to be modernized are Issues Tracking, Contacts and Custom list using a datasheet view
I'm certain that there was a Message Center (in O365 Admin) announcement about adding it for Task lists and a few other templates. I could be wrong.. but then why can I set it to modern if it's not supported yet? Shouldn't it be either auto-switching to classic or preventing you from setting it to modern in the first place? I believe this is what happens when you try to use other templates/features that don't support modern yet.
Yeah it should but might be why the errors. You100% sure it’s a task list template and not a custom list made to look like a task list? You can check under site content. If it’s a task list it’ll have the task icon for that list and it’ll be closer to the bottom. If not then it’s a custom list.
Yeah, It's definitely a default Task List.

I'm getting the same issue with a document library now too.  propsError.png

Console shows {"error":{"code":"-1, System.Xml.XmlException","message":{"lang":"en-US","value":"Data at the root level is invalid. Line 1, position 1."}}}

Interesting, I'm not seeing any of these problems in my lists or document libraries

For my library with the issue; If I delete the "Enterprise Keywords" column the issue goes away, turn Enterprise Keywords back on and it comes back.  I don't know if this helps with a tasks list though.