No, that's the contacts making er, umm, contact with the sim. Your signal strength is dependent on the phones antenna, the buildings or environment you're in and potentially any case you weave on the phone.
Yes, they do look deeper than I've seen before. Are you going from having service to no service at all?
I seriously doubt it's the SIM card, but we can hope that it is.Really all it does is provide authentication to the network, not provide coverage or signal strength.
I have these 3 lines down my sim. I had good signal tonight for like 2 sec but now my signals only 2 bars 4 Mbps LTE. Please see pic.