Network graph points to an incorrect merge commit parent

[sufftea]

Select Topic Area

Bug

Body

I merged branch n1 into dev without fast-forward. Here's how the graph looks on my side:

It looks the same in the UI version as well. That is to say, this is the correct representation and the problem has to be on the github's side.

Here's how that graph looks on github:

Notice the merge commit after n1: both of its parent pointers point at the same commit. That's doesn't make sense and is also impossible. This is what it's supposed look like:

I found a stackoverflow question about the same issue from 2014. Someone in the replies had contacted GitHub and had received a response saying they'll fix it. Apparently, this still isn't fixed.