The macOS Microsoft Teams version 1.00.208866 does not follow OS setting for time format in calendar view
The Calendar view incorrectly shows the time list in 12 hour, (am-pm) format, even when the OS uses 24 hour format.
When opening a meeting, the times noted there shows up correctly in 24 hour format.
Some parts parts of the world does not understand the concept of am or pm at all, we have done away with that in the previous millennium! :-)
MacOS Mojave 10.14.4