Yes you can run into serious problems. If you have a loss with the vehicle and the insurer finds out the vehicle is not in your name then the insurer is well within their rights to deny, at the very least, any physical damage claim. This is because if a loss occurs where there is damage to the vehicle you, since your mom is the actual owner of the vehicle, would suffer no financial loss since your mom is financially responsible for the vehicle and would be the one who suffers the loss. If you cannot prove what financial interest you have in the vehicle you cannot show you have an insurable interest. If you have no insurable interest you would get zero should there be a loss. So if the vehicle is stolen, and you have Comprehensive coverage, you would suffer no financial loss since you are not the registered owner of the vehicle therefore you would not have been able to sell the vehicle. Since you are the policyholder your mom would not be able to file a claim under your policy.
If you want to avoid future headaches I would strongly recommend you cancel your current policy and start a new one with your mom as the policyholder and you as the principal operator.

There is no problem with that. The important thing is when you drive the car, you must have an insurance.