My minuscule pet peeve is that having only one source where the number 5 is depicted with a triangle (all others show it as a separated segment, like the number 6 but shorter), that's how every article or library draws it. It's all because the guy who wrote a book about them saw that source first so he based his figures on it.
Here's a small summary about the numbers with many examples: https://www.unicode.org/L2/L2020/20290-cistercian-digits.pdf