Will not having a TM30 filed for my previous stay in Thailand cause issues for my return?

The TM30 is a requirement in Thailand where landlords must report the arrival of foreigners to local immigration authorities. If a TM30 wasn't filed for your previous two-month stay, it's generally viewed as a minor issue, especially if you don't extend your stay. However, it's important to ensure that one is filed upon your return to avoid any complications, particularly when doing a 90-day report or applying for extensions. The responsibility of filing the TM30 primarily falls on the landlord, not the foreign tenant.