Can't package HTML5 w/ SimpleHMD Plugin

My 4.8 project packages to HTML5 successfully. However, if I enable the SimpleHMD plugin (Window → Plugins → Virtual Reality), the project fails to package to HTML5 (but still packages successfully to Windows).

Has anybody else encountered this problem?

Yup, I have - there are a few HTML5 bugs in 4.8. I think it is supposed to be fixed in 4.9.