Pagination adds extra trailing slash at the end of some URLs

[thornsteps]

WordPress 5.5.1 pagination adds extra trailing slash at the end of some URLs.

Normally, our website's URLs don't have trailing slash at the end of the URL.

We have found some bug on the_posts_pagination() function on WordPress 5.5.1.

[At page 2 of a category]​https://stepstraining.co/strategy/page/2:
Previous link = ​https://stepstraining.co/strategy/
Page 1 link = ​https://stepstraining.co/strategy/

[At page 3 or more than page 3 of a category]​https://stepstraining.co/strategy/page/3:
Page 1 link = ​https://stepstraining.co/strategy/

All of the above URLs will 301 redirect to ​https://stepstraining.co/strategy --it should not have trailing slash at the end of the URL in the first place.

[At page 2 of a tag]​https://stepstraining.co/seo/page/2:
Previous link = ​https://stepstraining.co/seo/
Page 1 link = ​https://stepstraining.co/seo/

[At page 3 or more than page 3 of a tag]​https://stepstraining.co/seo/page/3:
Page 1 link = ​https://stepstraining.co/seo/

All of the above URLs will 301 redirect to ​https://stepstraining.co/seo --it should not have trailing slash at the end of the URL in the first place.

The bug was gone when we tested adding untrailingslashit() to below code:
File : /wp-includes/general-template.php
esc_url( apply_filters( 'paginate_links', untrailingslashit($link) ) ),

[lukecarbis]

Is this a duplicate of #52057?

[thornsteps]

Replying to lukecarbis:

Is this a duplicate of #52057?

I think it's similar. I opened this ticket 2 months ago and still have this problem on WordPress 5.5.3 .

At first, we don't have this bug until one day we did SEO checking again and found it.

[kaderavek]

#52057 was marked as a duplicate.

[SergeyBiryukov]

Adjusting the title, as the issue is not specific to WordPress 5.5.1 and was likely introduced earlier.

[djovanov]

Same issue, reproduced on WordPress 6.22 and Twenty Twenty Two on fresh install, without plugin's.
Any workaround solution ?

Trac ticket: https://core.trac.wordpress.org/ticket/51662

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