I know this thread is old and dead, but I just had the same problem and here's what worked for me.
Baseline: I'd went to the source applications on the web to confirm the 3 calendars I told S-Calendar to sync & display were set to my time zone (EST). Then I checked that the phone, under Date & Time settings, was set to auto update the time zone and was currently showing EST. Finally, under S-Calendar settings I checked the auto time zone box, that it currently registered I was in EST, and unchecked the "lock appointments to time zone".
Even so, when I opened an appointment, it showed both EST and UTC for the appointment, which was annoying but liveable. But if I tried to edit the appointment, it would only allow edits in UTC - which was unacceptable. Way too confusing. I'd be making appt mistakes all the time. Not very professional.
I installed Google Calendar also showed the two time zones I saw in S-Calendar when viewing an appointment. But when I edited an appointment, there was a drop down box for Time Zone that was filled in UTC. I selected the box and it asked me what country I was in (USA), and then gave me a list of US time zones to select - I chose EST - and voila! I could now edit my appointments in EST and viewing them only showed the appointment time in the current time zone - no more UTC!
I looked at S-Calendar again and noticed that when editing an appt, there was a light grey down arrow right under the UTC time. Clicking that arrow expanded that section and now showed a time zone box where I could change the appt time setting from UTC to EST.
Yeah!
Not sure how I wound up with this problem. Might have been because I skipped some of the initial phone setup when I got it earlier that day in the Verizon store. But in any case, this fixed the problem.
Hope that helps someone else with what's probably a rare issue.