Hi @Milton Camara , welcome to Microsoft Q&A forum and sorry for the trouble you are facing. This could be intermittent issue because of any parallel process.
Can you please check the schedule updates settings if any updates were planned in the period you were trying to scale up? You can check it from left menu Settings -> Schedule Updates.
Also, if possible please provide the region and current vs new azure Redis Cache Size you are trying to update to. I will try to replicate to confirm if this is generic or specific issue.