Quick release lever free spinning
Stop riding the bike until you know what's going on here. If you aren't able to work out what the issue is then find a mechanic who can look at it for you, losing the front wheel while riding is going to end up very badly for you. 

That fork should have 15mm axle and you say it's a QR so usually you screw the axle in and to then flip the QR like lever up to lock it. There is often a small screw that adjusts the tension needed to lock the lever so it may just be that that needs adjusting.  But if you're in any doubt as to the security of the wheel don't ride the bike until it's sorted.