Welcome to the club. As one that has been building entire enterprise platforms and adding unique features and functions for decades my vast experiences reflect that there will never be a shortage of people looking to claim others work as their own, even steal it to start another company as this happens very frequently yet just does not get as much attention as it should I believe. I have experienced this at every level even down to one claiming to have built and architected an entire company's systems which was entirely my own effort. I also have direct experience with developers stealing I.P. and starting "new" companies, being discovered, sued, losing the suit and then having their wages garnished for millions in restitution. This is sure to happen more and more as technology is built into all devices needed or not and thus business opportunities increase allowing others to apply those stolen ideas. There are A LOT of narcissist egotists out there and I would encourage everyone to avoid them at all costs as they are toxic to business.