I have been having trouble with my arrows landing consistently left with one of my bows.
It was driving me nuts, tried messing with strike plates, no real difference.
Also really spent a lot of time working on my form, that did not change anything either!
This afternoon I was shooting at one of my 3d deer outside the light was good and I was shooting down hill.
I could see my arrows flying sideways before the fletching corrected it. They were acting stiff. So I thought well maybe I did not get this bow/arrow combo tuned correct.
So after trying all the weights between 200 n 300 with no help, I went and had dinner.
After dinner I wondered if my brace height had changed.
Checked it, sure enough it had moved 3/8 of an inch!
Grabbed my bare shaft went back out to my shop where I can shoot 14 yds indoor.
Set up my IPhone on slow mo and videod a couple shots before changing it, sure enough flying stiff.
Put in 4 twists, flying a little better, 4 more turns and they are flying perfect and hitting where I am looking!
Used the iPhone on slow mo again to verify the flight for a few more bare shaft shots, the flight was just beautiful.
Lesson learned - check your brace height regularly, would have saved me a LOT of frustration the last 3 weeks!

So right batbow
If my BH is off, so is my shooting.  I check it every time I use my bow.

Deno

Something like that can drive you nuts, glad you found it. Here is what I do that helps.I shoot multiple bows and found the need to keep a sticker with bow stats on the bow. Includes brace height, nock point height, arrow shaft, point weight, tiller if ILF and fixed crawl distance if so set up.

I had that happen to me before. It was with a string that was about 6 months old to. For whatever reason it stretched. Good tip hear

Had a simular experience with nock height. New bow putting woods nose first in the dirt. My tie on nock point had moved up 1/4 in. I figured it out when I added a feather rest and did not need to adjust it.

M60gunner
I use waxed string for tie on knots. They don't move.

Deno

I keep an eye on my BH, measure it every now and then, regardless of the string material I'm using. I have a cheap ($2) Stanley 3' tape measure that really comes in handy for this.

The sticker is what I need to do, i did put the set up info on a notepad. But it's never where I am!
I believe this was a slow progression over 3 months ago when I set it up. My brain had been adapting.
But when I got the Centaur I went thru the whole set up with it, bare shaft knock height brace height - not exactly in that order.
When I was finished tuning the centaur, few days later I went and shot the Blacktail again, about missed the block!
So shot it some more with one eye closed to see where the arrow was pointing  when I was hitting center - I was pointing way right. Was shooting indoors and did not see that the arrows were not flying well.
Grabbed the Centaur shot it, arrows hit right in line with where they were pointing.
That's when I started shooting the Blacktail every other day to see if it was just me being off a - but it was always the same.
Then I would shoot the Centaur or the Acadian and they were always right on!
The trad bows are not quite as simple as one is led to believe!

Once the BH is good, I put a mark(dot) on my arrows, or use the old fashion fistmele.  Fist and thumb + 1/2 inch for me.
Deno

I had a guy give me a bunch of flack at a 3D shoot one day because i unstrung my bow and put 1/2 twist in the string and strung it back up. I randomly check BH, even if there is no problems. I did that day, and it was a tad low so I moved it up. He though I was nuts. I know where it is supposed to be, and I try to keep it there.

Bisch