"Ĉu vi havas kurson por komencanto?"

Translation: Do you have a course for a beginner?

[BintaFulani]

I am a native English speaker, and have taught English. I have never ever heard on of your alternative English translations: "Do you've a course for a beginner?"

[jxetkubo]

Looks a bit as if someone has automatically put in the alternatives “you’ve” for all “you have.”

[Sa967St]

My understanding is that you're allowed to contract "you have" to "you've" only when "have" behaves as an auxiliary verb (i.e. when it is used for perfect aspect).

[-Goca-]

Duo didn't accept "beginner", but "beginners". I will report it