Source tag in picture tag doesn't work correct

1. In hippo/blomreach document use ckeditor and choose source. 
2. Type for example
`<picture><source media="(min-width: 800px)" srcset="https://www.euroflorist.pl/img/300x/_big800@pl/BOU20_33.jpg" /> <img alt="" src="https://www.euroflorist.pl/img/300x/_big800@pl/BOU20_33.jpg" /></picture>` 
3. And then when you click save, ckeditor will change `<picture><source>` into `<picture><audio><source>`

Expected result

What is the expected result of the above steps?
Don't wrap source tag with audio in picture tag

Actual result

What is the actual result of the above steps?
Changing `<picture><source>` into `<picture><audio><source>`

Other details:

HTML-processor configurations is set to no-filter. With richtext it doesn't work at all even when I add source tag to configuration. source tag is deleted when I save document.