在使用navigationController popVC的时候之前的页面是空白的，怎么处理？

我使用demo，在page页里面，实现了代理方法：
- (void)virtualViewClickedWithAction:(NSString *)action andValue:(NSString *)value{
if (action) {
NSLog(@"action: %@, value: %@", action, value);
[self.navigationController pushViewController:[[GridViewController alloc] initWithFilename:@"Grid"] animated:YES];
}
}
我跳转到GridViewController，之后我popVC之后page页无法获取此页面的params参数，无法显示图片（无法加载URL），此时navigationController 中没有保存响应的VC，这里是怎么解决的？

Start with the demo's page implementation and virtualViewClickedWithAction:andValue:, then trace the push to GridViewController and the subsequent navigationController pop. Reproduce the return flow and inspect why the page parameters and image URL are unavailable afterward. Done means returning to the page preserves the needed parameters and the image loads correctly.

Written by the indexing model from the issue text.