Invited for final interview, rejected without feedback before stepping in the door

2 interviews deep at large firm, asked about interview availability for this week. This included an explicit statement that I would be having an informal interview to meet the team within a given time range in the next few days. All the ‘excited to meet you OP’ included and asking for suitable times.

Email this morning (I shall paraphrase): “I have decided not to advance your application”.

On asking for feedback to tailor my future applications, the HM said they had none and that there was nothing they could recommend.

Those dwelling in the recruiting world; what have I done wrong here, other than make any assumptions about what it means to be told I would be coming in for an interview?