The summer has been pretty hot the past two weeks or so. 30C outside and perhaps 33C inside the closet. We've since changed the on-hours to 1am to 1pm so it isn't so hot while the lights are on.looks like you still got heat problems. and also to me they look stretched or something. how close is your light to the buds? Maybe try getting the lights closer to the tops about 6 inches away.
Because of a tall plant the lights couldn't get further down without touching this plant. But now the buds on this plants have weighed it down so I've moved the lamp further down so it's about 10 cm from the top of the tallest plants and about 30 cm from the smallest plants.