Pull request across forks compares changes with previous commits rather than base branch

Hello, today I made a new pull request, with jeffalo/wasteof.money:master as the head branch and pufferfish101007/wasteof.money:vue-post-components-(; as the compare branch. You can find this pr at Vue post component (; by pufferfish101007 · Pull Request #58 · jeffalo/wasteof.money · GitHub. However, when looking at the files changed section, it seemed to be comparing the changes I’d made on my fork to previous commits on my fork, rather than to the current version of the head branch - for example, looking at the LICENSE file diff, you’d have thought that currently there is no LICENSE file in jeffalo/wasteof.money:master - but it does. This is the case with seemingly every file in the diff - it’s either comparing it to a previous version of a branch on my fork, or a previous version on the fork I’m pushing to.
I have closed the pull request, as it obviously wasn’t working properly, and attempted to make a new pr from the same branch, and then the master branch - and none of them correctly compared the files.
Can anyone figure out what’s going on here?
Thanks for any help you can give.