Many blocks appear to flicker severely when behind stained glass. As an example, end portal blocks when placed behind stained glass seems to "struggle" to determine whether it should render in front or behind the stained glass ,resulting in flickering that may potentially cause seizures in players with epilepsy.

It's worth noting that my pc has a GTX 1660 Ti, and I am using the absolute latest drivers available. So it's not a graphics driver issue.