Don Cullen

It may be designed to behave like that, but when Mojang added "respawn_anchor_works" for use in datapacks, that caused a breaking change with the current behavior with the exit portal under that circumstance.  In short, "respawn_anchor_works" is not compatible for use with The End due to how exit portal and respawn anchor works.  I see you're saying this is a duplicate of MC 253536 – it is not a duplicate, although related.  In MC 253536, because of lack of user-specific cases, it cannot be stated as a problem and was correctly categorized as not a bug and design as intended. 

However in this issue, I am pointing out a design problem in where "respawn_anchor_works" and respawn anchors becoming incompatible when used within The End dimension when using the exit portal, which is a very specific case.  The fix for that is very simple, on usage of exit portal, check to see if respawn point is within the same dimension, if so, send player to world spawn, otherwise, send to player spawn point.

So I disagree with the categorization of this being a change request, it is a bug within design specs in where certain conditions are in place and trigger incompatibility with design specs.  Ask the engineers, pretty sure they'll agree they didn't intend for that to happen when they added "respawn_anchor_works".

There should still be a spawn check; if the respawn point is within the end as opposed to other dimensions, the exit portal should then take the player back to the world spawn in overworld on account of there being no alternative spawn points. I doubt it was intentionally designed so the player would be trapped at the end and that the only way out would be to destroy their current respawn point, defeating the point of having it in the first place.

This is still an issue.  Using invisibility potion with no armor whatsoever (with similar vein as guardian) should result in my not being seen by Endermen, but if I make eye contact with them, they still get provoked and attack. This is in 1.16.