Piston update fails on initial download

Launcher fails repeatedly at the same step in initial game install/launcher update, citing that some downloads failed. However, all files have been logged as successfully downloaded.

 

System information:

Processor: Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz

Installed RAM: 16 GB

System Type: 64-bit operating system, x64 based processor

 

Windows specifications:

Windows 10 Pro V. 1909

OS build: 18363.592

 

Java version 1.8.0_241

Java SE Runtime Environment: 1.8.0_241-b07