Consider the following scenario:
You use Microsoft Skype for Business 2016 that has the Korean or Japanese language pack installed.
You set the Short time regional configuration option in the Korea or Japan region to the tt h:mm format on your computer.
You set the Long time regional configuration option in the Korea or Japan region to the tt h:mm:ss format on your computer.
You send instant messages (IM) to someone on the client.
In this scenario, the hours setting in the IM conversations displays only PM or AM for Korea or Japan and don't display any number-based time value.
Note To set the Short time and Long time regional configuration options in the Korea or Japan region on a computer, open the Region and Language, item in Control Panel, click the Formats tab, and then select the tt h:mm option in the Short time format and select the tt h:mm:ss option in the Long time format.
To fix this issue, install the March 8, 2016 update (KB3114846) for Skype for Business 2016.