The time in the marcela127 observations page is utc, so 5 hours ahead of the Bogota time. When it’s 8pm in bogota the UTC time will show as 1am the next day.
As another example, I am in New Zealand, and I make an observation right now it will show for me as 10 Mar 2020 15:32 +13:00 as we are in daylight saving time. But it would show on the observations page as 10 Mar 2020 02:32 AM UTC. If I had made the observation earlier, say 3 hours ago, it would show for me as 10 Mar 2020 12:32 +13:00 and on the observations page as 9 Mar 2020 11:32 PM UTC, ie back into the previous day!
or are you saying that it should show them all in the same timezone?
That setting for the timezone is just the timezone your own observations will be set to, unless you specifically state a different timezone. Many cameras do add a time zone code as well, but if you enter a manual time without a timezone then the system knows what to put based on your settings.