`$replace` rules may break some websites

[Alex-302]

Please answer the following questions for yourself before submitting an issue

• [x] Filters were updated before reproducing an issue
• [x] I checked the knowledge base and found no answer
• [x] I checked to make sure that this issue has not already been filed

AdGuard Extension version

4.4.49

Browser version

Firefox 135 x64

OS version

Windows 10 x64

Ad Blocking

AdGuard Base filter, AdGuard Mobile Ads filter

Privacy

AdGuard Tracking Protection filter, AdGuard URL Tracking filter

Social

AdGuard Social Media filter

Annoyances

AdGuard Annoyances filter

Security

No response

Other

No response

Language-specific

AdGuard Ukrainian filter, AdGuard Russian filter

What Tracking protection options do you have enabled?

No response

Issue Details

Steps to reproduce:

1. Disable current $replace rule (also disabled in filters) feed$domain=vk.com|vk.ru,xmlhttprequest,replace=/banner:/bann_er:/,badfilter
2. Add vk.com$domain=vk.com|vk.ru,replace=/<title>Лента новостей<\/title>/<title>Лента новостей111111<\/title>/
3. Open vk.com
4. Open view-source:https://vk.com/feed

Expected Behavior

3. The site is NOT broken, NO error popup
4. Лента новостей is replaced by Лента новостей111111

Actual Behavior

3. The site is broken, error popup is shown

Screenshot 1

No errors in uBO.

4. Лента новостей is replaced by Лента новостей111111 in view-source:https://vk.com/feed

Screenshots

Additional Information

Related to

https://github.com/AdguardTeam/AdguardFilters/issues/196322#issuecomment-2663592309 https://github.com/AdguardTeam/AdguardBrowserExtension/issues/1001

[Alex-302]

@maximtop