Today MiniTool found KB4457128 again and has just installed it.

[17:50:07]: Installing "2018-09 Cumulative Update for Windows 10 Version 1803 for x64-based Systems (KB4457128)"... Succeeded (0x00000000)
[17:51:07]: Installing updates: Succeeded (0x00000000)
[17:51:07]: Searching for updates
[17:51:20]: Searching for updates: Succeeded