Glide Custom Cache key

I load image by using load(customModel) instead of load(imageUrl) directly,and there are some extra data in the custom model,like uid and imageurl etc...,and In the class customLoader which implements ModelLoader class,I use uid in the customModel class as the cache key,like ObjectKey(model.uid),now I have a problem,after several days,when I load image ,I can't hit the disk cache and have to load image from network again.I don't know why