Postprocessing shaderpass dispose method does not work

Questions
1

I am removing my three.js canvas from the DOM with a destroy() method that looks like this

destroy() {
            cancelAnimationFrame(this.id)
            this.renderPass.dispose()
            this.customPass.dispose()
            this.composer.dispose()
            this.renderer.dispose()

            window.removeEventListener('resize', this.resize)
            window.removeEventListener('mousemove', this.mouseMove)
        }

But the dispose method on my this.custompass which is an instance of ShaderPass does not work. If I remove this.custompass from the chain of passes, I can successfully delete the canvas from the DOM and re-init it without any errors. If I add it to the render chain and try to dispose it, I get these errors every frame:

[.WebGL-0x7006e1a900]GL ERROR :GL_INVALID_FRAMEBUFFER_OPERATION : glClear: framebuffer incomplete

Any idea if I am doing something wrong or this is an issue with the dispose() method?

(edited for clarity)