Strange redstone behaviour

Redstone gets really weird when it powers redstone (as a button) to it and when the powered redstone of the repeater gets back to the repeater and stays "on"

TL;DR? See the images. Basically, this is a compact version of RS NOR Latch (Memory Cell).

What I was expecting to happen was:
When redstone was powered by the button, the redstone should stay "off".

What actually happened was:
The redstone stayed "on" for unknown reasons.

Steps to Reproduce:
1-Get a button (with a block to a attach him with), a repeater, and some redstone.
2-Put some redstone then put a repeater, then connect it with the circuit. As shown in the images below.
3-Get a button and a block and press it!

Examples:
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