I have saved a profile with and without drift enabled.
At LUT generation I have generate LUT (1) with drift enabled (for a file saved without drift) and (2) without drift enabled (for the same file saved with drift enabled).
The two LUT are slightly different. Is that correct?

I have noted that at LUT generation the Limit Luminance Max (not clicked) is different for the two cases: in case (1) it is the value without drift (and it does not change enabling drift), in case (2) it is the slightly modified value coming from drift enabling at saving time.

Off course available to send the relevant files for allowing you replicating.

PS: generally talking I don't like you are allowed to save a file with drift fix, re-opening and saving it again with drift fix (so allowing applying twice drift fix by mistake).

Yes, that is all exactly as expected, as on one you have used Drift to alter the Profile, and in the other to directly alter the LUT Generation.

The two are very different processes, and while the results will be 'similar', they will most definitely not be identical.

Steve