The same thing is happening with my Galaxy S8 plus. I just noticed this yesterday but I am not sure when it started.
When a full day event (one day or spanning multiple days) is initiated from my computer and then synced to my phone the entire event is pushed one day before.
When a full day event is iniiated from my phone it appears fine on my computer. (Microsoft exchange)
I'm having the same problem with my note 9 on Verizon. Just noticed this today. This appears to be specific to Microsft 365 accoutns only. Did a test through my google calendar with an all day event and it shows on the correct day. Office 365 however pushes any all days events a day earlier. Can we get a fix on this soon?
Having the same issue for Office 365 account on Galaxy Note 8 via Verizon where all day events are shifted back one day. Just started after the recent update to the email app. DON'T UPDATE to anyone watching or you'll have issues!! Please fix this ASAP as we are professionals that depend on our phones to organize our day. This is critical to many people's daily routines. Hope you are watching Samsung!
Same problem on Note 8 Verizon. Pushes event start time to prior day at 8:00 PM. To determine if this was Microsoft or Samsung or Google's fault, I exported my outlook calendar from Outlook 2016 on my desktop to a .CSV file. Sure enough, the exported CSV shows 8:00 PM the day before as the start time. This appears to be Microsoft's issue.
Couple days ago ALL my cal events were duplicated on Phone, but one massively annoying day earlier. Deleted them all, and that deleted them from server and left the "good" items on the phone.
Deleted account off phone, cleared cache/storage for Calendar app, and resynced. Syncs ok.
Slight nuance I notice...my recurring all-day items sync fine, but all of the single-event all-day items are one day early on my S8 (TMO-US). I use Office365 and Outlook 2016 client...and see that in both of those interfaces all is fine, only on my S8 does the problem present. I also concur with prior messages that this likely started with the recent email app update...haven't yet tried removing it to see what happens.