WhatsApp is very strict when it comes to template message approval. Any message that they feel is in some way promotional are rejected.
You can get some idea of the WhatsApp policies for post-session message templates here: https://support.morph.ai/portal/kb/articles/3-03-facebook-policies-24-hour-limit
Also, there are multiple factors that determine the final rejection of a template, like which team/individual is processing the templates. You can always change the formatting for the rejected templates in compliance with the WhatsApp policies and apply for approval again, hoping it gets approved.