Updated builds.

build/three.cjs

@@ -15346,7 +15346,7 @@ function WebGLCapabilities( gl, extensions, parameters ) {
 
 	}
 
-	const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl instanceof WebGL2RenderingContext;
+	const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl.constructor.name === 'WebGL2RenderingContext';
 
 	let precision = parameters.precision !== undefined ? parameters.precision : 'highp';
 	const maxPrecision = getMaxPrecision( precision );

build/three.js

@@ -15351,7 +15351,7 @@ console.warn( 'Scripts "build/three.js" and "build/three.min.js" are deprecated
 
 		}
 
-		const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl instanceof WebGL2RenderingContext;
+		const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl.constructor.name === 'WebGL2RenderingContext';
 
 		let precision = parameters.precision !== undefined ? parameters.precision : 'highp';
 		const maxPrecision = getMaxPrecision( precision );

build/three.module.js

@@ -15344,7 +15344,7 @@ function WebGLCapabilities( gl, extensions, parameters ) {
 
 	}
 
-	const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl instanceof WebGL2RenderingContext;
+	const isWebGL2 = typeof WebGL2RenderingContext !== 'undefined' && gl.constructor.name === 'WebGL2RenderingContext';
 
 	let precision = parameters.precision !== undefined ? parameters.precision : 'highp';
 	const maxPrecision = getMaxPrecision( precision );