Exactly, this AA question (Anti-Aliasing filter) gave Nikon something to crow about starting about 10 years ago. Removal of this filter from a digital sensor is a change to the 'original design' of digital sensors / cameras as initially released about 20ish years ago. Canon has decided the image quality risks of moiré patterns and certain false color issues out way the benefits of marginal overall sharpness. As the worldwide leader with nearly 50% of the total market, Canon has judged their customers are not demanding this change given the issues the filter removal includes.

The problem- Everyone is opining on an issue that the OP has but the OP has not posted the image in question. Y'all can talk about this "rule" 'till the close come home and go away and come home again but without the image, it's all moot!

When teaching, studying, learning and analyzing COMPOSITION, there are some definitive rules and guidelines that can help in expanding various theories and methodologies. Most folks are taking a class, reading a book, or receiving critiques. etc WANT some definitive answers and rules to apply. Without an image to discuss, the written or spoken rules mean nothing and sometimes amount to a load of useless technobabble and a geometry lesson.

There are times when the "rules" need to be purposely broken to obtain the desired effect.

Some newer photograher place diagrams on the camera's viewing screen so as to conform to various compositional theories. Others prefer a grid. Someof these diagrams are built into various cameras and cell phone cameras. Perhaps this is a good learning practice but it is like training wheels on a bicycle- after some practice, it is time to remove the wheels and achieve a natural sense of BALANCE.

A good and effective composition starts at the camera so whenever possible, it is a good practice to look for elements such as leading lines, rule of thirds, horizon placement, etc. so it is wise to try to shoot from various angles and heights, change focal lengths, alter perspectives, and refine the first shot. Final cropping and composition can be addressed in post-processing. On the other hand, if you are shooting a fleeting bird or animal, a sports event, etc, somets it is best to shoot first and ask questions later. Always try for effective composition but not at the expense of losing a great spontaneous shot or expression.

I can sympathize with the submitter in a critiquing situation because oftentimes they are left with unanswered questions or confusing issues. I can also sympathize with the judge or critic. Offering a real comprehensive critique in a limited time can be difficult. If a particular element in an image is given a negative critique, just saying "NEVER" or "DON'T DO THAT" is insufficient unless it is accompanied by a reason why it is a distraction or detrimental to the visual effectiveness or impact of the total image.

Again, if anyone wants a second opinion from folks here on the forum, for heaven's sake POST THE IMAGE!

As their name suggests, the purpose of a leading line is to lead the eye into the shot. Because of that, most leading lines start from either the bottom edge or the lower half of either side. I would not describe your reed as providing a leading line. I frequently have the edges of roads and paths starting from a corner and I've never considered that to be a mistake, although I have a slight preference for starting them from close to the corner rather than exactly from the corner.

In your shot, if you cropped from the left a little, the reed would be entering the frame from the side rather than from the top. The top entry point creates an impression of the reed hanging from above, which may suit you - but obviously not the judge. I suppose it's one of those divisive points that create divergent opinions. Calling corner entry points a mistake is putting it a bit too strongly IMO, but like centred horizons, the safe option seems to be to avoid them.