فَالْأَصَحُّ أَنَّهُمَا مَلَكَانِ لَمْ يَصْدُرْ عَنْهُمَا كُفْرٌ وَلَا كَبِيرَةٌ
The stronger view is that they were two angels who did not commit disbelief or a major sin.
On this account, any language of reproach is not taken as proof of grave unbelief or a major transgression; some explanations treat it as admonition connected to trial or a lesser lapse. Establishing the precise occurrence of an event, however, requires its own evidence.
One cannot replace the general teaching about angelic protection with a claim of grave sin simply because a story mentions a penalty. Nor does possible reproach by itself establish a verified case of disobedience.