Double-messages just leave you confused.
Have you ever had an employer make you responsible for something, but then take your authority away. It’s confusing. Stepparents get these double-messages a lot early on when their stepchild appreciates them for being a parent, but then gets annoyed with them for being a parent. Yes, give me an allowance, but don’t discipline me. The answer to this confusion is to not second-guess yourself. Act with consistency; build trust over time; and let your spouse handle punishment for a while.