Your theme is outdated. When you fork your own theme you have to keep an eye for the changes in the default theme.
Here at /signup:
(left yours, right Peafowl)
Missing the "accept terms" checkbox. This was added to v3.10.14 due to GDPR.
Here, missing a property on footer.js
I hope that in the future you use overrides rather than full theme swapping as it avoids this kind of issues.
For now, you should compare both theme folders and add/remove the conflicts manually. Use a folder compare tool like Winmerge or Beyond Compare which I strongly recommend for this kind of task.