Safari

• Fails to inerit grid-template-* property. CodePen, Twitter
• Can't read text-decoration in shorthand.
• Fails to recognize data-uri SVG filter in CSS.
• The url(#id) is not recognizable if the id element is inside Web Component.
• CSS animation not working for pseudo elements inside Web Component. Twitter.

Chrome

• Fails to read data-uri format for clip-path property. CodePen.
• Using innerHTML to write 485 nested divs with absolute style and pseudo element will crash browser. CodePen.

Web Component

• The @property syntax is not recognizable inside Web Component.
• Nesting Limit Inside Web Component. CodePen, Twitter.

Limitation

Not actual bug.

• The length of Custom Property value has limit. Source Code.
• The maximun length of Grid columns or rows is 1000. The number may differ between browsers. Spec.