Will returning to Thailand after a two-month absence cause entry issues for expats?

You could have issues, especially flying into Bangkok. To mitigate these make sure you have the three things that they may try to catch you out on.

Cash - 20,000 baht or equivalent in a major currency. Must be cash. A bank statement or phone app or credit card won’t suffice.

Onward ticket - proof of onward flight within the 30 day allowance.

Accommodation - booked accommodation for the first few days of your stay. Doesn’t need to be the whole time, just proof that you’ve booked somewhere.

If it doesn’t change by then you will also need a ThailandPass to enter.