Mechanized airlocks erroneously delete mass

I tested another setup. I was attempting to determine if the closing door deletes mass when it has an adjacent door below it, but not next to it. Yes, this setup also deletes mass.

 

FYI I tried to reproduce this with no mods. I disabled all my mods but then my sandbox save game wouldn't load anymore, so I gave up on that.

I'm also attaching a smaller Player.log, since the last one was huge. I deleted the file then opened the game to simplify the log file.

This log message, which appears many times, is suspicious:

[18:40:18.842] [1] [WARNING] Invalid cell modification (mass greater than element maximum): Cell=180705, EIdx=163, T=1, M=0.001, Vacuum max mass = 0

 

Player.log

This issue also happens if there is a solid tile in this setup (the right door is the last to close):

If there is a solid tile, about 10% of the mass is deleted (tested on a very long period, this number is accurate to +/- 1%).

If there is no solid tile there (like on the screenshot), no mass is deleted.

6 hours ago, Fradow said:

This issue also happens if there is a solid tile in this setup (the right door is the last to close):

If there is a solid tile, about 10% of the mass is deleted (tested on a very long period, this number is accurate to +/- 1%).

If there is no solid tile there (like on the screenshot), no mass is deleted.

It doesn't need a solid tile near/above the door.

See my report Mechanized Airlock intermittently destroying water.

This happens here because the two tiles of the airlock do not actually close at the same time. The primary tile (bottom if it is vertical, left if it is horizontal) will close a fraction of a second before the secondary tile. This pushes the water to the right in the "buggy" setup, then deletes the remainder as it has nowhere to go. Fradow's example is similar except vertically oriented.

I'm actually making use of this behaviour to push things rightwards using horizontal doors and upwards using vertical ones.

But it is nonintuitive and unexpected, given the symmetry of the animation.

Edited January 22, 2022 by Yobbo