I just got this new weird error after last update to v12.8, theme generation error

this is the content of the error

Preformatted text`Traceback (most recent call last):
File “/home/frappe/frappe-bench/apps/frappe/frappe/website/doctype/website_theme/website_theme.py”, line 112, in generate_theme_files_if_not_exist
File “/home/frappe/frappe-bench/apps/frappe/frappe/website/doctype/website_theme/website_theme.py”, line 81, in generate_theme_if_not_exist
theme_path = join_path(bench_path, ‘sites’, self.theme_url[1:])
TypeError: ‘NoneType’ object is not subscriptable

and i was unable to open the website with internal server error for 10 min, did restart 3 times, untill it worked again on its own
please help, as this is the second time this happens after last update to v 12.8

You can try a

bench update --reset

and also check this post