Interstage joints breaking when entering slow motion

This is a faily complex booster. But in short how it should work: when SRBs and external fuel tanks are empty they detach themselves. (launch rocket normally vertical at max thrust to see regular operation).

To replicate bug. Lock heading, set throttle to max, activate stage. Wait a little bit (after about 100m above ground) then toggle the time mode, for me, toggling a couple of times between 2x speed and 1/4x speed would cause a premature activation of regular separation events.

The way the separation events are coded: when a designated section of a fuel tank's mass gets below a certain threshold, it will broadcast a message to the craft saying which tank is ready to be separated, then separation motors and insterstages receive the code and activate.