If one reports (denuncia) the loss/theft of a vehicle in Spain when it is recovered a further report must be made that it has been recovered.
That applies no matter who finds the vehicle, even the police. The report cancelling the first report MUST be made. It is a very serious matter not to do so.
If not done the vehicle will remain listed as stolen
PS Do not expect to be told you must do this. It will be assumed you will know as it is the law in Spain