Formatted WYSIWYG Viewer Not clearing view when HTML Header Tags appear after unformatted text.

[scrub-dev]

Describe the bug

A clear and concise description of what the bug is.
When Entering text and then adding a header html tag ie: <h1></h1> the viewer interprets each key press while entering text between the header tags as a new header.

For example, typing:

test

would display

t

te

tes

test

.

The variable it is using remains valid to the original inputted text and pasting the example text in yields the correctly formatted view.
When swapping to just markdown, the h1 tags are removed but the WYSIWYG Viewer still displays the incorrectly formatted text.

Problem is present on demo as well.

To Reproduce

Steps to reproduce the behavior:
Using Toast UI 3.2.2 with Vue as a Vue Component.

1. Create a toast UI editor component.
2. Visit the site
3. Type out this is a test with <h1>a html header element </h1>
4. Swap to the Markdown only tab
5. Re-open the WYSIWYG Viewer

Expected behavior

The output correctly displays the this is a test with

a html header element

output in the WYSIWYG Viewer.

Screenshots

Desktop (please complete the following information):

• OS: Windows
• Browser: Chrome
• Version: Version 132.0.6834.83 (Official Build) (64-bit)