As far as I can tell, Stian Jenssen apologised about the way the comment had been made and interpreted, but not about the substance. Specifically:

A day later, he gave an interview to the same newspaper, VG, that had reported on his original comments. “My statement about this was part of a larger discussion about possible future scenarios in Ukraine, and I shouldn’t have said it that way. It was a mistake,” he said. But Jenssen did not walk back the idea that a land-for-Nato-membership deal could ultimately be on the table. If there were serious peace negotiations then the military situation at the time, including who controls what territory, “will necessarily have a decisive influence,” the chief of staff said.

So clearly at least some people in NATO consider that a peace deal may entail territorial concessions. Which like it or not is a realistic position to take.