Using deprecated replacevars show the wrong Snippet Preview length

[benvaassen]

• I've read and understood the contribution guidelines.
• I've searched for any related issues and avoided creating a duplicate issue.

Please give us a description of what happened.

When using a deprecated meta variable (#9893) in the snippet preview, the length doesn't change (the green bar stays the same length) but the meta variable is showing on the frontend.

Please describe what you expected to happen and why.

I expected the title length to change and the snippet preview to show the current year.

How can we reproduce this behavior?

1. Open a (new) post.
2. Add the variable %%currentyear%% in the snippet preview title and see that the title length feedback doesn't change.
3. Check the source code and see that the %%currentyear%% is replaced with 2018 and the length differs from the one in the snippet preview.

Additional context

This is an issue because my title length in the snippet preview is different from the actual length shown on the frontend. This can happen when I rewrite old posts which might still have the deprecated replacevars in the title (or description). My length feedback would be incorrect and my title could possibly be cut off in the Google search results without my knowledge.

Technical info

• WordPress version: 4.9.6
• Yoast SEO version: 7.7
• Tested with theme: Twenty Seventeen

[ghost]

Please inform the customer of conversation # 394272 when this conversation has been closed.