Known Bugs

Help Link

When I press the "Help on this function" link I am getting redirected to the Microsoft COUNT function page.
This only affects the Help Link when you are editing a cell that already contains a custom function.
The Help Link works fine when you are inserting a custom function into an empty cell.

link - github.com/OfficeDev/office-js/issues/2487 

Runtime Logging

You might see messages in the log file that are classified as errors but are not errors and have been classified incorrectly.

link - learn.microsoft.com/en-us/office/dev/add-ins/testing/runtime-logging 

The following is not an error.

Monitorable, Manifest, Issue encountered while parsing manifest, Parsed manifest targeting different host, add-in ID : ??, 
Location : Error at element "Hosts" : Add-in manifest doesn't support current client, Line=259, CharPosition=7  

The following is not an error.

Medium, Current host not in add-in's host list SolutionId: ??, Version:1.0.0.0, StoreId:\\