If, after moving your units, you used the "RUSH" command, it's normal for the units to suffer a decrease in their Hit Points (HP). The game informs you about this. You can verify this yourself by following these steps:

Order the unit to move to another location.

Use the "RUSH" command.

Tap the "i" (Information) link.

In yellow text, the system will explain that "Army is currently moving 50% faster at a cost of 5 Hit Points per hour."

For detailed information about this and many other game mechanics, please visit the https://wiki.conflictnations.com/Main_Page

Additionally, the Discord server is quite useful for gaining a deeper understanding of the game: https://discord.com/invite/con