Workaround:

        private void radChat1_ItemFormatting(object sender, ChatItemElementEventArgs e)
        {
            ChatTimeSeparatorItemElement separatorElement = e.ItemElement as ChatTimeSeparatorItemElement;
            if (separatorElement != null)
            {
                if (separatorElement.Text == "TODAY")
                {
                    separatorElement.Text = "TODAY_EN";
                }
                else if (separatorElement.Text == "YESTERDAY")
                {
                    separatorElement.Text = "YESTERDAY_EN";
                }
            }
        }

It would be very convenient to scroll to a specific message when a lot of messages are available.

Please refer to the attached sample project and follow the steps from the gif file. The scrollbar needs to be in the middle.

Note: the issue can be reproduced without action list as well.