Do words crossover from lesson to lesson?

Sorry if this question is ignorant, but I am wondering if vocabulary I learn in previous courses will be drilled in subsequent courses? I am in Spanish (Spain) 2 and I am not positive I seeing words from Spanish 1. Or is the idea I am supposed to go back to the Spanish 1 course and review?

No, a course’s content is restricted to itself and won’t “blend” into a subsequent course. However, the SRS (Spaced Repetition System) will result in words showing up as “up for repetition”. Consequently, you’ll have to open the course and start a session to review them.