If one prays Witr with three, it has three forms
Machine translationRead the Arabic original
The questioner : If one prays Witr with three, it has three forms. Yes. Yes, and he prays two rak'ahs and finishes with one.
The Shaykh : He prays two and says the taslim.
The questioner : No, no, may Allah reward you, yes.
The Shaykh : I said three.
The questioner : It is two; I am present with two.
The Shaykh : Yes, fine.
The questioner : The third is the Maghrib prayer, meaning?
The Shaykh : Well done. The third is to pray Witr like the Maghrib, and this is prohibited; it is not prescribed. That is, he recites the tashahhud in the second rak'ah and then comes with the third. This is not prescribed; it is prohibited.
The Shaykh : He prays two and says the taslim.
The questioner : No, no, may Allah reward you, yes.
The Shaykh : I said three.
The questioner : It is two; I am present with two.
The Shaykh : Yes, fine.
The questioner : The third is the Maghrib prayer, meaning?
The Shaykh : Well done. The third is to pray Witr like the Maghrib, and this is prohibited; it is not prescribed. That is, he recites the tashahhud in the second rak'ah and then comes with the third. This is not prescribed; it is prohibited.
Source
قناة «فضيلة الشيخ محمد بن صالح العثيمين»، 2349إذا أوتر بثلاث فلها ثلاث صفات📔 الشرح الممتع على زاد المستقنع - ابن عثيمين — youtube.com
The Arabic text is a machine transcription of the audio recording.