Section 27 of Transfer of Property Act: What is Going On Here?

I am seriously at my wit's end with Transfer of Property Act. I was trying to understand Section 27 and I am so confused. It says that when land is sold and the seller hasn't executed a proper conveyance deed, the buyer can still take possession of the land. But then it adds that if the seller has created any prior charges on the property, the buyer's rights are affected. Is it just me or it's like the section is saying two completely different things? In Kedar Nath v State of Bihar (1951), the Supreme Court said that the buyer's possession is protected under Section 53A of the Indian Easements Act, which is a welcome clarification. But what about other cases where the buyer is already in possession and the seller creates a charge? Can someone please clarify this mess for me?