Interesting. I play tested it several times before submitting it. Thanks! I'll take a look!
Edit: I attempted to recreate the error and cannot. I did as you said; after speaking with poppy, I touched the crystal, spoke to the professor, and then attempted to leave the area. Instead, I got the message (the one you're supposed too) saying that you must equip your weapon and armour before leaving.
Edit Edit: Was there anything else that happened? Are you sure about that order? I'm going to try a couple things and see what happens.