Let's look at your second sentence first:
2) It is being organized.
This is a passive voice construction. The existence of some semantic actor or agent is implied, but the subject of the sentence serves a different semantic role. We can transform this into an active voice construction by supplying an agent as the subject: Something is organizing it.
The complete verb is "is being organized". This employs the passive voice, present tense, continuous aspect, and indicative mode. Since the verb carries an action from an agent to a patient, it is a transitive verb.
1) It is being cautious.
This is not a passive voice construction. As far as I can tell, this sentence has no voice at all. This is a copular construction. The verb serves to link the adjective "cautious" to the subject "it".
The complete verb is "is being". This employs the present tense, continuous aspect, and indicative mode.
It is easy enough to regard the adjective "cautious" as a modifier of the subject "it". It is also easy enough to regard the participle "organized" as a modifier of the subject of its sentence. The difference is that the adjective does not imply any sort of agent, but the transitive verb does.
In both cases, "is" marks the present tense and "being" marks the continuous aspect. Only one sentence employs the passive voice, but both sentences are present continuous constructions.