I have never had this issue until today.
The warnings I am getting are:
Issues CA-929, CA-926, CA-925, CA-911 and 6 others do not have a value for the 'Estimate' field. Values entered after the start of the sprint will be treated as scope change.
Includes issue(s) currently hidden by a Quick Filter or the Instant Filter.
I have looked, and as far as I can tell I have the correct permissions.
Thanks in advance for your help!