Succinctly -- looks like healthy plants to me. light is not too far away nor too close You are fine.
-- could still test boundaries if you haven't. (more or less light via distnace from canopy, but rememer this impacts blanket of coverage... sometimes distance is mor about how much area you have to cover well... lowering light decreases footprint size and increases difference between hotspot areas and weaker areas of coverage) A lux meter can help -- a free app on phone. can see if adjusting height makes to much of a poportional difference from center to outskits of coverage...
Knowing the umol/s of light produced by light can also help verify you are safe... 35-40DLI is a good starting point for ambient co2 of indoo grow. umol/s divided by area of coverage in m^2 gives you ppfd,, you can then reference a DLI (daily light integral) table with you hours of light and determine a faily accurate DLI provided... if 35-40, you are up nea max fo ambient co2... some trial and error to flesh out exact boundary is needed. Too many variables are different between gardens that this is never exact but will be very close. Much better/faster than blindly trying to find a relative maximum light provided.
all possible causes...
It can be a sign of too little, too much, or a happy plant...
So, you have to eliminate possibilities.
ppl like to incredulous about 'too little'. Once had a belligerent response about it, lol. love it when i'm called stupid and it's eally their ignornace, bwahaha. You can take a plant, remove from the grow lights, leave it on a table a while or even a few days with just ambient/normal house lighting and see the results for yourself... they'll be praying hard and it isn't for a good reason.. its because there's not enough light and it is trying extra hard to find some. This is a possible reaction to too little light, as well as other causes being possible.. it is not discrete cause and effect.
too much light: They also can try to reduce their surface area by praying if light is too intense.. usually other symptoms coincide or it progresses to wilting or burns on the leaves. too much light can do a vaiety of things to the plant.. just depends on how intense and how long. Tacoing will likely coincide in this case.
armed with DLI, basic observances of plant and expeience you can easily discern which is which. Exp takes time to build up, but the othe 2 you have day 1 if you want to.