The script "Labels of all enemies" does not show the labels of all people in the sector, but only the enemies and only in battle mode. For example, if there are 20 people in the sector, but only 10 of them are hostile to the player, then the script will show 10 marks, not 20.
This script is useful during combat as a "technical reconnaissance tool" to estimate the location and number of enemies in a sector, or to find a hidden "last enemy".
I use this option in map encounter battles so all are hostile to the player, the problem is the first encounter will show enemies the second encounter will not show enemies.
I test this using map encounter, not city battle.
After a few travels around the map, I managed to come across a random encounter where the markers are not shown. This happens when combat mode is not fully activated. At the same time, you cannot freely leave the sector (as during the battle), but the color of the squares is green, not yellow, and the enemies on the minimap are shown as yellow dots, not red. After a while, the battle mode is activated, then the squares turn yellow, and the dots on the map are red and all marks appear.