Cross Grid Control Group Activation

On one of my builds I noticed that several timers would trigger control group actions for blocks on a different and completely separate grid from the one they are on, after separating by merge block (while also not activating blocks of the same group on their own grid that they should be able to affect)

The bug shows up reliably enough that I was able to make a blueprint to reproduce it:

https://mod.io/g/spaceengineers/m/cross-grid-influendce-demonstrator

What's supposed to happen:

The drone in the blueprint is supposed to be able to fire four missiles in sequence. These missiles use a two-stage activation sequence:

1. Stage 1 activates the forward thrusters, detaches the missile from the ship and starts a 1 second timer located on the missile.
2. Once the timer for Stage 2 triggers, it activates side thrusters, deactivates the main thrust override, arms the missile, and lets the onboard AI blocks take over.

The stage 2 Blocks are all in one common Block Group called "Missile Stage 2" shared across all 4 missiles. This shouldn't be an issue, because by the time it is used, the missile is separated from the ship and thus shouldn't be able to affect the blocks on the other missiles.

However, instead it ends up activating the "Missile Stage 2" blocks on a different missile (and all other missiles attached to that one's grid), while also not activating them on its own missile.

How to Reproduce

Paste the blueprint and enter the cockpit.

Pressing 1 will launch a missile, which will then activate the thrusters on all the other missiles 1 second later.

However, for easier demonstration, instead press 2, which detaches all four missiles from the ship. The main grid can then be removed entirely. Afterwards go to one of the missiles and trigger the timer on it. No matter which missile you pick, the timer will always trigger group on the second missile from the left, rather than the one on its own grid.