I find a glitch of CGContextSetFillPattern glitch only on Ventura.
If the size of the pattern is a multiple of 4, there will be a hole in the upper right corner of the pattern in the first column.
I make a demo Xcode project here.
I have tried all three CGPatternTiling enum values, all have the same result.
I tried your project and it does reproduce. I notice that I don't see the glitch if I increase the step parameters to CGPatternCreate, putting gaps between the cells.
You should send a bug report with Feedback Assistant. This forum is not an official channel for reporting bugs.
By the way, you can simplify your code sample a bit. Instead of passing the size as a dictionary, pass &_size in the CGPatternCreate call, and then say CGFloat size = *(CGFloat*) info; in the callback.
Thanks for your reply. I'll use Feedback Assistant to report this.