Blur in image processing

[srgtest]

Hello!
Version 1.4.7.
There are problems with image processing - they become blurry.

For example, here is a picture: 018f5ca0-5535-7a9f-9187-b41db718aa0e.jpg (in addition)
When processed, it becomes blurry.
Here are the parameters:

{"params": {"path":"fit-in/320x416/filters:format(webp)/https://***/018f5ca0-5535-7a9f-9187-b41db718aa0e.jpg","image":"https://***/018f5ca0-5535-7a9f-9187-b41db718aa0e.jpg","unsafe":true,"fit_in":true,"width":320,"height":416,"filters":[{"name":"format","args":"webp"}]}}

There is blur if you do not specify the size for resizing.
I previously found out that sharpen affects this - if you specify it, the sharpness increases. But then it breaks other images.
I can't attach the result because it's in webp format.

What can be done about this?
The same behavior on version 1.4.15.