Thanks for the report.

Visual Micro should be making the same decision as the Arduino IDE, using the same decision tree from their specification.

Can you confirm that both are the same library (just one downloaded from GitHub directly I assume)?

Could you also confirm which library it is (either the GitHub URL or attach the library.properties file from it so we can replicate the issue?

Could you also attach the verbose build log from Visual Micro for us to review as well?

Thanks for the detail and the update.

Can you attach a screenshot of the vMicro > General > IDE Locations Screen with the Arduino 1.6/1.8 IDE selected for us to review?

Thanks for the screenshot.

From this and the logs, Visual Micro has been configured differently to the Arduino IDE, which could explain most of the issues in the compilation, and decisions made on which libraries to use, as well as the different ESP8266 board package in use by each IDE.

Could you try:
1) Updating the Optional Physical folder for Downloaded Board packages to:
C:\Program Files (x86)\arduino-1.8.19\portable

2) Amend the Sketchbook Location to the same as the Arduino IDE is using:
C:\Program Files (x86)\arduino-1.8.19\portable\sketchbook

After this click vMicro > General > Rescan Toolchains and Libraries so it refreshes all board and library information.

Then if you click Build > Clean Solution, and recompile again, it should yield the same result as the Arduino IDE.

I believe when portable mode is in use the overrides should not be needed at all, however having them there will ensure it is looking in the same places while we work through this issue.