Please build the app and again migrate the site.
I’ve shared a suggestion:
If you’ve installed ERPNext in version 15, make sure the hrms is also in version 15 to prevent errors.
If the hrms is in the development branch, switch to it:
bench switch-to-branch version-15 hrms
If you’ve uninstalled or installed the app, do this:
bench get-app --branch version-15 hrms
This is because the hrms app has a version 15 branch.
I hope this is clear and helpful.
Thank You!