Individual Option HTML tags being wrapped with Select Tag when switching to visual editor

[iseekdesign]

Scenario:
When pasting code that includes a form dropdown select input into post (html view) everything works as expected. Switching to TinyMCE editor modifies the Option tag and wraps the code in Select therefore splitting the dropdown into several dropdowns with one item each.

This happens for example when pasting PayPal code (with product options) into a post/page.

Code example:

This code

<select name="myselect">
 <option></option>
 <option></option>
</select>

Becomes this code

<select name="myselect">
 <option></option>
</select>
<select name="myselect">
 <option></option>
</select>

[linuxologos]

Happens in 3.2 too.

[SergeyBiryukov]

#18534