This could be coincidence, but it seems very doubtful.
Two weeks ago, I got a Moto G5s, swapped my number to a new skinny Sim, put it in, and within an hour, received a spam call (answer and no-one's there). That was around mid-day, since then there have been several more, but all in the afternoon or evening.
I've had this number for a very long time, and been on skinny for quite some time.
Spam calls to this number are extremely rare
My memory is that the phone only had the initial setup completed, nothing else was installed.
I'm curious to know if anyone else has had the same. I'm finding it hard to accept it might be coincidence.
On a related note, the app "NoPhoneSpam" looks to be doing a good job rejecting the calls.