I think the user wrote that he/she is using a 5D III, and in that case, yes, Lr/ACR is respecting the in-camera crop (aspect ratio) setting but does not have a built-in way to recover the full recorded raw image. That ability was newly added in ACR 7.2/LR 4.2 for newly-supported models only (e.g., Sony RX100, among others), whereas the 5D III support was added in earlier versions of ACR/LR. As you correctly noted in that thread, that's where DNG Recover Edges can help.
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