Desync issue

[jjanisze]

Factorio & Factorissimo version number
Release: full, space-age
Version: 2.0.72 (build 84292 win64)
Factorissimo 3.11.1 (initially). Downgrade to 3.10.15 had no effect on existing save.
Please post both the Factorio and Factorissimo version numbers here.

Describe the bug
Frequent desyncs for both players on a 2-player multiplayer server.
Heavy mode CRC fails every tick in heavy mode when reproducing in single-player.
Disabling Factorissimo3 causes heavy mode to not exhibit any CRC failures.

To Reproduce
Steps to reproduce the behavior from a new save:
Unknown.

Expected behavior
No CRC failures in heavy mode.

Screenshots

Additional context
Uniquely, one Warehouse3 has 1001 robots in it's invisible roboport, with one robot persistently not being able to dock. Not sure if root cause or incidental.

Save file & log
103mb, beyond GH limit
https://fromsmash.com/Factorio-Desync-Save-Github