A while ago, I was at a customer providing support for their Office 365 implementation and they had a strange issue regarding date metadata which had been added to the document itself as a field.
When they opened the document in Word Online (View mode), it actually displayed the date -1 day. If they opened the document in “Edit” mode, it showed the correct date. Editing the document in the Word client application also displayed the correct date.
I started testing this in our own Office 365 tenant to see if this was a general issue or just a glitch.
I added a date/time column to a document library. I created an empty document and added it to the library. I set the review date for the document.
I opened the document in the Word client and added the field inside the document.
The correct date is inserted. When I saved the file and reopened it in the Word client application, again, the correct date was displayed.
I returned to my document library and opened the document in Word Online.
And there you go… instead of showing me the correct date, it shows me the date -1 day.
I had this tested by some other people as well and they also confirmed this behaviour.