Yes, I have DNN 7.3.4 and Events 6.1.5 (both the latest).
I've also done some more testing and this is what I have found. My site requires verified users:
1. Created new user, did not change default time zone from International Date Line West when registered
This user had the error in both of the modules. Updated the user profile to be Eastern Time. No more error.
2. Created new user, changed the default time zone to Eastern Time when registering (It's a mandatory field).
This user also had the error. This time all that i did was go in and click update on the profile, I didn't do anything with the user's time zone. No error.
3. Created new user, left the default time zone (International Date Line West) when registered.
This user had the error. Like #2, I simply went into the profile and clicked Update (didn't change the time zone from International Date Line West) and the errors are gone.
So it doesn't look like it's the Events module at all, but something with the profile of the user when registered.
Time to look into that...