If your landlord doesn’t allow smoking indoors, why would they make an exception for weed?

You’re probably right.

Depends on your lease agreement. If there’s a no-smoking clause then your landlord has reason to be upset if you smoke inside the place. That’s never stopped me, just be discrete and courteous to your neighbours (don’t stink up the place).

Otherwise, it’s none of their business. Even if it were illegal.

Any chance of you clarifying what “LPT” means here? Which of these: https://acronyms.thefreedictionary.com/LPT