The upper lake level fluctuation throughout that period only amounted to 0.31 The daily fluctuation on average, during stable times, is seldom less than that. And water temp only fluctuated 4° during the same period.
Try as you may you cannot predict or accurately explain why fish do what they do. If you depend on stable conditions then the safest place to be, year round, is in the mid-lake area (7mm to the toll bridge) where the least amount of change (temp, clairity, current, elevation) occurs.