My guessing is that when you switch sequence, goes to the first keyframe of the new sequence, and then gradually sets the new time (so yeah, the sun will move from the original position to the new one).
About the suggestion from @ . If I understand it correctly, let’s think I have 5 keyframes in Sequence1, and then I have only 1 keyframe in Sequence2, which is at 15:00. means that to switch correctly I should only change from Sequence1 to Sequence2 at 15:00 (so the original sun position of Sequence2 is the same as the current of Sequence1), right?