I think he's saying he has been moving to the next company within 2 years after starting a job. Not all 3 companies in 2 years.
Let's wait for them to clarify. If it's 3 companies in 2 years, I'd not bother them. If it's a third company where he's leaving at 1 year 11 months - it'd look completely regular / fine for me.
That sounds like a huge loss for the employer.
> Being clear that it wasn't a positive sign to them. Is it really that strange, or were they maybe used to bigger company culture and expectations?
The question they’re asking themselves: What is the chance that you’ll be staying with them at least 3 years.
Based on your CV: close to zero.