In the linked questions to Sum of the series $\sum_{k=0}^{r}(-1)^k.(k+1).(k+2).\binom{n}{r-k} $, I get:
but the correct parsing of the title is Find the remainder when $\sum_{r=0}^{2014} \sum_{k=0}^r (-1)^k (k+1)(k+2)\binom{2019}{r-k}$ is divided by 64:
I uploaded a video of my clicking refresh here. At first it's okay, then it changes to the incorrect version.
I'm on Firefox. Changing my zoom doesn't affect anything.
Question: Why is MathJax parsing incorrectly for this linked question?