DI ECU and ECU are two different things.
You stated that the service tech said they didn't have to remove the ECU which is true.

You need to specify.
And I'm sure you asked about them removing the ECU and not the DI ECU.

10k after the recall and it could have been a number of things. which is why they aren't helping you.
Like was said above if it was something they did it should have started way sooner.
Bolts do work themselves loose sometimes. Mine did.

No, I sent him the service invoice that literally said the direct injection ECU was not bolted on correctly. So either he didn't look at what I sent him or he was incorrect/dishonest (assuming you are indeed correct). I didn't specify in the thread here, so sorry for the confusion.

My issue is that the DI ECU was fine for 60k miles. Then it was removed, reattached, and failed within 10k miles. If it failed within 10k miles from factory, it wouldn't be acceptable. That said, I don't think their work is warrantied for that long so ultimately if they don't want to take responsibility, whatever.

BUT it's pretty terrible customer service to shift blame and not acknowledge the reality that they probably didn't tighten the DI ECU properly, especially when a Toyota service center said as much. A simple reimbursement of the cost to correct their error seems like a small ask, IMO.

You got off easy. While nursing my car back from Laguna Seca with rod knock after the recall blunder, my clutch went out in heavy traffic on the freeway leaving me stranded out in the middle. Cause of clutch failure? Toyota dealer forgot to tighten down the clutch fork. Insult to injury

It is also possible he misunderstood you since it is not called a DI ECU. It is an injector driver module. It basically takes the signal from the ECU and does the work so that the ECU is not handling those loads. Kind of like how you use a switch with a relay to activate something so that the switch is not taking the load.