iOS 12 downloading problem?

[3:16]

I have a limited WiFi date /per day (2GB) so when my data limit ends & I try to switch to another wifi network while downloading update, the estimating remaing progress bar gets stucks on where I disconnected the first WiFi network,

Instead of pausing the download it remains stuck on where it left the first connection and never completes.

Is there anyway to pause the download?