Transparency Impacting Legibility
The "clear" transparency of some elements is impacting legibility since the underlying UI can be seen through them pulling your focus to it, such as the following two examples.
Things do not need to be using transparency (mimicking the OSD style) when they are not overlaying rich content--that popover especially does not need to have this style, toasts might be a different case since they are transient but it still applies if one is over text and the toast also has text.