Having Troubling Hosting UE4 in Perforce, "Plugin X Failed to Load..."

I attempted to follow this article (link) on hosting a fresh copy of UE4 for myself and others to work on, but when anybody but me pulls latest, they always encounter an error stating that some plugin failed to load. The plugin changes, but seems to always be editor related (eg “PlatformCrypto” in a game that doesn’t use that plugin)

If someone encountering this error then builds the game with Visual Studio locally, the error goes away (even on subsequent launches). Therefore, I’m fairly certain I’ve made a mistake in setting up my Perforce server.

I’ve been submitting all changed binaries files under Engine/Binaries and MyGame/Binaries with the following .p4ignore file, but I’m fairly convinced I’m not updating a file (or a group of files) that I should be. Does anybody know what I’m missing or doing wrong?

My .p4ignore file:
UE4.sln
*.suo
*.pdb
*.opensdf
*.sdf
*\DerivedDataCache*
*\Intermediate*
-Debug.
FileOpenOrder/
!MyGame\Binaries\ThirdParty*
\Saved*
!
\Saved\SaveGames*.sav
*\obj*
Engine\Programs\UnrealBuildTool*

I figured it out; the “.modules” files were all labeled as write-locally in P4, and therefore were never checked out or updated server-side