The problem of that option is that the AI never use that kind of unit in a amphibious noncombat movement, even if it is technically possible. Because the human player can do it without any problem.

If you have a unit with isAA property, which by standard contains the above mentioned unit option at true, and you want to have the AI to use this isAA unit in a noncombat phase by amphibious transport to strengthen an already conquered territory (same round or the later), then you have to make the following pair of triggers for each nation with a always-true-condition:

<attachment name="triggerAttachmentAmphibiousNonCombatTransport" attachTo="Nation" javaClass="games.strategy.triplea.attachments.TriggerAttachment" type="player">
<option name="conditions" value="conditionAttachmentAlwaysTrueCondition"/>
<option name="when" value="before:NationNonCombatMove"/>
<option name="unitType" value="isAA-unit"/>
<option name="unitProperty" value="canNotMoveDuringCombatMove" count="false"/>

The second trigger just changes:

<option name="when" value="after:NationNonCombatMove"/>
<option name="unitProperty" value="canNotMoveDuringCombatMove" count="true"/>

This is funny because i just allowed a noncombatmovement unit to combatmove in a noncombatmove phase to be able to be transported and unloaded by amphibious transport by the AI.
And it works. Without problems so far.