cannot read properties of null(reading 'toLowerCase') getting this error and is consistent

Hi ​@anusham598930,

Could you please share the relevant interface/expression and the steps to reproduce this issue?
Thank you

This must be happening at the interface level, could you please be more specific ? 

We will need more details on how you came across this error or relative code to help you further!

A user has reported this error to me also, and provided me with a nearly identical screenshot.  On my end it is a known-good task, and opens for me when I log in with a basic user test account and open the task.  The user confirms they are opening the task from Chrome on a PC, and the error persists even after logging off and back in.

The interface in question has no trace of anything named “toLowerCase”, in fact such a phrase is not found in my entire environment when doing a search-by-expression, so this seems to be some sort of internal error.

This is in our PROD environment which upgraded to 26.9 a few days ago.

FYI: Appian Support has officially advised that this could be an issue with stale browser cache items after an Appian environment version upgrade, so to have any affected users attempt to clear their cache and cookies, and then retry.