ive gotten dried out leaves from having a fan blowing directly on them too, just another thing to check if you have one (better to have it bouncing off a wall or your light so it spreads around a little). looks good though i wouldnt worry too much.
what fan are you using(extraction and circulation) and what are your temps like? didnt see them mentioned but hard to skim through the block of text.
i wouldnt worry it looks healthy anyway,
lowering it and letting it grow up to the screen will probably sort it. im sure growth will resume soon.