Edit History

Try clean cache of browser and prestashop.

In Chrome

On your computer, open Chrome.

At the top right, click More .

Click More tools  Clear browsing data.

At the top, choose a time range. To delete everything, select All time.

Next to "Cookies and other site data" and "Cached images and files," check the boxes.

Click Clear data.

Clean cache prestashop :

You can try disable Smart cache for CSS  too.