Thai uses แล้ว (already) for both. Confusion between past and present perfect. Thai PDF solution: A table in Thai showing that present perfect connects to ตอนนี้ (now), while past simple is just เรื่องเก่าๆ (old story).
Based on teaching experience at Thai universities, these are the top errors. A Thai-annotated PDF is invaluable here.
If you are a Thai student, office worker, or freelancer trying to master English, you have probably typed the phrase into Google at least once.