I look all over the internet for the same pattern, then compare. Try to stick with patterns that have instructions for the different sizes. Like Jinny Beyer has pattern for Hunter's star in 3 different sizes. that is what I look for. the videos are great because I can review and take notes. I do that often with Jenny Doan videos.

Not only have I found mistakes in free patterns but also in patterns I paid for. Bought a purse pattern at a quilt show a few years ago and found numerous errors in it. I emailed the designer of the pattern asking for clarification and never got a response. I will NEVER buy one of her patterns again. Anyone can make a mistake, but to ignore a plea for help in inexcusable.

I agree with your first response. Go back to the website and see if you are supposed to increase the size before printing. Sometimes things can really be aggravating. Hope you can solve the problem

The only time I had a problem with a free printed pattern I failed to add the 1/4 inch. It did not say to do that but when I did and made another block it worked out. I always keep scraps to try a new pattern before I cut into my fabric I have for the quilt.

Could it be that the pattern did not allow for the seam allowances?

I think the pattern designer would like to know if they made a mistake so I think I would contact them if there is a way to. Also she may have meant to say a 7 1/2" block instead of a 101/2". Either way there is a mistake somewhere. I haven't ran into that problem yet but I think I would contact her. ( or him) Good luck with whatever you do

Make sure you printer is on actual size not print to page. I have made this mistake several times

10.5" square paper pieced block won't print in full on a standard sheet of copy paper, I'm guessing there was a second page to print and then tape to the first.
Is the block cute at the current size? :)