Hi grow friend
I think at the moment if things have bn going good for u it's not a great amount to worry about it could be a case of genetics as this is quite often the case but if u have change the level of height of your light or for example where ir plant is getting taller then it could be that she's feeling the light more than before ...if u have the room to increase the height of your light then maybe move that up slightly but I wouldn't say at this point it's too much to worry about ...if it is genetics then this is how she will be until the end now , try to keep a note book writing any changes u make and that will give u something to look bk over if things persist or if anything else begins to happen good luck growmie 🍃