This bug only happens when structural bug subscriptions are *not* enabled which is currently only the case on qastaging (for members of betatesters). The code has changed since this was reported but it now found in update_mute_after_subscription_change which is called even without the mute option being on the page. Also, this seems to not be critical anymore since it does not hinder the actual subscription.
Anyway, easy fix, I'll do it anyway.
This bug only happens when structural bug subscriptions are *not* enabled which is currently only the case on qastaging (for members of betatesters). The code has changed since this was reported but it now found in update_ mute_after_ subscription_ change which is called even without the mute option being on the page. Also, this seems to not be critical anymore since it does not hinder the actual subscription.
Anyway, easy fix, I'll do it anyway.