
As far as I can tell this behavior does not happen in any other roboport in the game. The behavior persists after restarting the game and loading the save.
Factorio Version: 0.16.51
OS: Ubuntu Linux 18.04.1 LTS
Mods:
AutoDeconstruct 0.1.11
autofill 2.0.1
bigger_slower_trains-016 1.2.0
even-distribution 0.2.10
EvoGUI 0.4.302
Moar-Radar 0.1.0
Power Armor MK3 0.1.7
rso-mod 3.8.1
Squeak Through 1.2.2
Saved game: https://we.tl/t-HjnLyhpmjj
You can see the bug in action at: https://vimeo.com/309003356 . At the start I insert a single logistic robot and it disappears (you can see 0/0 robots), then I add 6 more robots, and you can see only 2 make it out alive (0/2 robots), then 48 seconds in I add 5 more robots, again, only 2 make it out alive, giving (0/4 robots), then at the end, around 1min 35sec the robots one by one return to the roboport and vanish.