Environment: Odoo 17 CE with OCA Subscriptions Addon

I'm encountering an issue with the automatic generation of invoices using the OCA Subscriptions module. When I manually click on "Create Invoice," the formatting is correct. However, when the CRON job triggers invoice generation at the end of the defined period, the resulting invoice loses its formatting and is sent as a plain text version.

I have reproduced this issue on a fresh Odoo instance using Runboat.

Does anyone have a solution or workaround for this issue?