Time Zone color event bar. Also import from Tripit

I’m not quite sure how the time zone feature is supposed to work.
This is what I did: Manually entering an EVENT: Flight from NY, leaving Tuesday - 10 PM -4 UTC] to Singapore arriving Thursday 6 AM +8UTC.
This resulted in the color calendar event bar extending from Tuesday to Wednesday.
Why does the color calendar bar not extend to Thursday?
The event entry, however, remains correct: Tuesday 10 PM -4 UTC and Thursday 6AM +8UTC

The same flight entered in eM Client via TRIPIT shows START: Tuesday 10 PM END Wednesday 5PM
The DESCRIPTION reads : START: Tuesday, 10 PM END: Thursday 6 AM
Again, color calendar event bar extends from Tuesday to Wednesday, not Thursday.
Seems that the imported info from TRIPIT is experiencing a problem.

Can someone help me understand this?
Thanks.