Same here, but I’m on v3.4.6 (Stable channel).
Confirmed, it was working before this update, and it no longer works now for any user. I just updated my Discourse instance to v3.4.6. Would it be possible to make this updated Glimmer implementation only be installed for users on v3.5.x and offer the previous version for v3.4.x?
BTW thanks for this extremely essential component, it really should be in core Discourse. 