The bug
When viewed from inside on an armor stand, some parts of the dragon head block have visible z-fighting.
Linked issues
discovered while testing 1
is duplicated by 2
Attachments
Comments 13
More or less fixed in 19w41a since entity insides are no longer rendered. Keep an eye out for regressions, though.
Another bug which is MC-190127 describes that it also happens when placing a Dragon Head and then viewing it from the inside in Spectator mode.
You don't need to add this to every ticket you create.