-e: see title
--workaround: reopen project and the compile errors should go away
--no errors in 2018.1.9, starts failing in 2018.2.0, still repros in 2019.1a5

-repro:
--create new project
--under Assets create a "WebGLTemplates" folder
--add a WebGL template with a JS file in there
--NOTICE a recompile is triggered and you get errors for stuff from the JS files included in the template
--reopen the project
--notice the errors are gone now