Seeing this issue as well in apple devices. Can't reproduce here, but multiple users reporting the issue. Will check error logs tomorrow and report back.
Anyone seeing any Errors in the logs?
Also, I noticed on my customers environment they have GAL enabled, and used simple CSV import for user creation, so have a lot of users with profile name "N/A", I wonder if the NA breaks SM trying to build the email to field in compose window?
Kyle Kerst Cameron Solutions LLC www.cameron-solutions.com