"Mereka memberi selamat kepada kami."

Translation: They congratulate us.

[Jspharmando]

Should be “Mereka memberi UCAPAN selamat kepada kami.”

[Ms.Fixer]

Just in case, I asked other native speakers.
https://hinative.com/questions/18302209

I agree with you. With "ucapan" is better because Duolingo primarily target language beginners. We can use the phrase without "ucapan" only toward close friends.