Please give us a description of what happened.

When creating a post using the How-To block in Gutenberg, there's a noticeable lag when you get to 15+ steps.

Adding the first few steps is fine:
Video: https://imgur.com/6ipyIGG

But when it reaches 15 or more, it starts to lag.
Video: https://imgur.com/a/1fpNiNd

Please describe what you expected to happen and why.

Shouldn't lag even with 15 or more steps.

How can we reproduce this behavior?

1. Activate Gutenberg
2. Create a new post and use How-To block
3. Add steps and enter step title until you reach 15-20 steps
4. Notice the speed difference when typing the title/description

Technical info

• If relevant, which editor is affected (or editors):

• Gutenberg
• Classic Editor plugin

Used versions

• WordPress version: 4.9.8
• Yoast SEO version: 9.2.1
• Gutenberg plugin version: 4.6.1
• Tested with theme: Twenty Fifteen