I'm on Windows 10, X1 version 3.1.3.39 beta with the most recent updates for the dongle and mouse

So I'm playing around with input nesting and have a setup I like where I can use these buttons as one input but with a combo I get media controls.

I have it set up so various mouse movements do various things, which you can see in the image, and they all have block parent mappings turned on.

The thing I'm asking about is that, even with block parent mappings on, if I release the right trigger before I release the left trigger, the release mapping of the left trigger still fires, but in the inverse case, if I release the left trigger before the right trigger, the release mapping is correctly blocked. However, the right trigger release mapping is blocked regardless, which is why I had to add an additional right trigger push release mapping so that Ctrl doesn't get stuck down if I use the media gestures I made.

Is this a bug, or does the block parent mapping not block in some cases?