The only other mods are Stack Combinator, Editor Extensions and Picker Dollies. I placed a few combinators and holos, and it even worked for a bit, but suddenly it started crashing.

The mod Holographic Signs (1.2.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event holographic_signs::on_configuration_changed
LuaEntity API call when LuaEntity was invalid.
stack traceback:
    [C]: in function '__index'
    __holographic_signs__/control.lua:128: in function 'ValidateAnimations'
    __holographic_signs__/control.lua:102: in function 'ReadRunTimeSettings'
    __holographic_signs__/control.lua:79: in function 'setup_mod_vars'
    __holographic_signs__/control.lua:93: in function <__holographic_signs__/control.lua:92>