We could also perhaps view Chiang Mai and Krabi as the future for all IMM, just trickling down slowly. I was reprimanded (gently) for signing an "illegal contract" and advised in future to only sign rental agreements as per the Krabi scenario. Useful info perhaps.
Your signed rental agreement is enough for imm. Happened to me. Short interview only & no fine for you. But be aware it will trigger an investigation of your landlord by tax etc & all may not end well for them. We ended up moving. 😏