Special Rules say: "Commando units are hidden at all times, unless they end up their movement in clear terrain, attack an enemy unit or voluntary choose to do reveal themselves." A few lines further we read that "A hidden commando team is revealed [...] when it [...] was detected by Reich units."
How does this "detection" work ? For example, what happens if a Reich unit enters an hidden enemy occupied hex ?
This mission only works with the Concealment rules in mind.
See Rulebook page 17:
Any land unit in a cover hex (e.g. urban, woods, shellholes), not in LOS of an enemy recon unit and not marked as Finished, is considered to be concealed. Concealed units receive a +1DV bonus when attacked. A unit ceases to be concealed as soon as it moves or fires (i.e. thus revealing its position), an enemy recon unit has a clear LOS to its hex or an enemy unit enters a hex adjacent to its position. The bonus is added to the defending unit against any type of attack except assaults (e.g. both artillery and air units have a hard time striking concealed units without recon information).
Especially this rule is important:
A unit ceases to be concealed as soon as it moves or fires (i.e. thus revealing its position), an enemy recon unit has a clear LOS to its hex or an enemy unit enters a hex adjacent to its position.
The scenario special rules indicate that the commando teams aren't revealed when they move, only when they end their move in open terrain. Just consider them to be "extra-stealthy".
However, this leaves the question: Can the Puma (Recon unit) detect the commando teams when in LOS?
There's nothing in the scenario special rules that speaks against this.
But if we consider that the LOS of units in the game is basically infinite, I wouldn't use the Recon rule for this scenario.
Just imagine a Puma moving back and forth in hex AA8 and AA9. :-)
So, to put it in a nutshell, Commando units are detected when a Reich unit enters a hex adjacent to them.