Sky Fly the practice has existed for a long time and is certainly not uncommon. It appears that it is becoming more and more common.
There are several aspects to this.

1 QR are uncertain about some aspect of your booking. It could be as simple as the method of payment (for example use of a credit card for the first time) or several other reasons.

2 In some airports airlines are required to check travel documents before issuing a BP.

3 Some destinations may require airlines to check for valid visas etc. before allowing passengers to fly.