TC rules (from exp. 5 rulebook).
NOTE: A light Infantry unit that moves will battle with one-half
the number of blocks, rounding up or down, depending on the
National army. The light Infantry unit may not melee. Other units
may battle before and/or after the skirmishing light Infantry unit
in the combat phase. However, immediately after the skirmishing
light Infantry unit’s ranged combat is completed, the unit
must either move back to the unit’s original hex or remain in
its current hex.
page 8, right column, Light Infantry Skirmish eplanation,
if you (or any of your opponents) want to search and read itself