Resigned effective immediately, announced the same day due to "personal reasons" is not a good look. Anyone who's spent a sufficient amount of time reading $BIGCORP press releases immediately sees how it stands out from the usual PR fluff.

In situations where I have seen that in the past, the person was caught in grievously bad, unambiguous case of sexual harassment, racism or something equally socially despised.

If this is not the case, Intel's PR people are doing a serious disservice to Keller in the way the announcement has been structured.

Generally if a higher level executive resigns due to actual "personal reasons" or a family tragedy, and it's an amicable departure, it's announced with at least a few weeks notice.