This is a general information regarding the patch erpnext.patches.v11_0.set_default_email_template_in_hr #08-06-2018
This patch requires the system to have an Email template by the name “Leave Approval Notification” and “Leave Status Notification”. However, the email template name is localised (e.g. “Statusänderung eines Urlaubsantrags”). Therefore, this patch will fail in any case where this install wizard was done in a language other than EN.
Workaround (personal opinion, not official): exclude the patch using the patch log and make sure the value is set in the HR settings.