Problems using $ in regexp templates

[volgaleoking]

Previously, the configuration in nginx 1.22.0 was used with the lines:

subs_filter '?t=$Time$' g;
subs_filter '#EXT-X-MEDIA.+TYPE=SUBTITLES.+\n$' rg;

but when switching to nginx version 1.26.1, errors began to appear as follows:
nginx: [emerg] invalid variable name in /etc/nginx/...
and
nginx: [emerg] match part cannot contain variable during regex made in /etc/nginx/...
in the process of studying the problem, it was revealed that the $ symbol was to blame, but any attempts at escaping did not lead to success.
Only after changing regexp templates:

subs_filter '\?t=.Time.' rg;
subs_filter '#EXT-X-MEDIA.+TYPE=SUBTITLES.+\n' rg;

the configuration was started successfully.