Error while running event ch-concentrated-solar::on_robot_built_entity (ID 14)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
    [C]: in function '__index'
    __ch-concentrated-solar__/control/database.lua:81: in function 'linkMirrorToTower'
    __ch-concentrated-solar__/control/database.lua:158: in function 'linkMirrorToTowerIfCloser'
    __ch-concentrated-solar__/control/database.lua:392: in function 'on_built_entity_callback'
    __ch-concentrated-solar__/control.lua:33: in function <__ch-concentrated-solar__/control.lua:32>

Save to 100% reproduce:
https://disk.yandex.ru/d/iWb_lq8E5pekkg

Note that this won't happen without the mods, but I was unable to determine which one execatly causes that behavior.

Steps to reproduce:
1. Download the save
2. Open the save file with all mods from the save game
3. Open map view
4. Q, R, Shift-Click (Select solar tower via pipette, rotate the cursor, shift-click to create a building rotation request)

Is not caused by sandbox and/or editor extension stuff, I was able to caught this in the my Freight Forwarding playthrough

Upd. #1
Not affected by ghosts, only caused by the robot upgrade requests.

Thanks for the report, although sorry to say I'm very busy currently so fix date unknown.
Should be able to fix the stuff you pointed out with the laser tower too, agree on your points.
Thanks