When a moving contraption snaps into place, if two Redstone Contacts are facing each other, the one that is not on the contraption will always stay ON unless updated on the detector side.

I replicated it with pistons, gantries, and mechanical bearings
This issue has already been mentioned here on a previous version: #1744

Here is a video example : https://youtu.be/CDHdrtI2PXA

#1723 #1559

However, they mentioned smth about this in a recent commit.

• Fixed blocks not updating their neighbors when being assembled into a contraption

But they didn't close any of regarding issues.

they will close the issues once 0.3.2b will be ready