Occurs with both player and bots.

The mod Miniloader (1.15.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miniloader::Custom event (ID 260)
miniloader/circuit.lua:51: attempt to index local 'target' (a nil value)
stack traceback:
miniloader/circuit.lua:51: in function 'copy_inserter_behavior'
miniloader/circuit.lua:78: in function 'sync_behavior'
miniloader/circuit.lua:170: in function 'sync_partner_connections'
miniloader/circuit.lua:247: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>
[C]: in function 'raise_event'
miniloader/lualib/onwireplaced.lua:104: in function 'raise_on_wire_removed'
miniloader/lualib/onwireplaced.lua:220: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>
stack traceback:
[C]: in function 'raise_event'
miniloader/lualib/onwireplaced.lua:104: in function 'raise_on_wire_removed'
miniloader/lualib/onwireplaced.lua:220: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>

Thanks for the report!

Thank you for fixing that first one so fast! Got a new one; happens with in place upgrade.

The mod Miniloader (1.15.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miniloader::on_robot_built_entity (ID 14)
miniloader/lualib/util.lua:404: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
miniloader/lualib/util.lua:404: in function 'apply_settings'
miniloader/lualib/miniloader.lua:153: in function <miniloader/lualib/miniloader.lua:137>
(...tail calls...)
miniloader/control.lua:111: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>

Don't know if it'll help much but I just got a very similar error [K2+SE] when deleting a circuited miniloader with the decon planner; edit: just happened when i tried to pick it up manually as well (for context it was an input loader into a storage chest). Edit #2 all is well in
1.15.2!
The mod Miniloader (1.15.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miniloader::Custom event (ID 256)
miniloader/circuit.lua:51: attempt to index local 'target' (a nil value)
stack traceback:
miniloader/circuit.lua:51: in function 'copy_inserter_behavior'
miniloader/circuit.lua:78: in function 'sync_behavior'
miniloader/circuit.lua:170: in function 'sync_partner_connections'
miniloader/circuit.lua:247: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>
[C]: in function 'raise_event'
miniloader/lualib/onwireplaced.lua:104: in function 'raise_on_wire_removed'
miniloader/lualib/onwireplaced.lua:220: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>
stack traceback:
[C]: in function 'raise_event'
miniloader/lualib/onwireplaced.lua:104: in function 'raise_on_wire_removed'
miniloader/lualib/onwireplaced.lua:220: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>

Placing down the loaders with bots also causes an error:

The mod Miniloader (1.15.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miniloader::on_robot_built_entity (ID 14)
miniloader/lualib/util.lua:404: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
miniloader/lualib/util.lua:404: in function 'apply_settings'
miniloader/lualib/miniloader.lua:153: in function <miniloader/lualib/miniloader.lua:137>
(...tail calls...)
miniloader/control.lua:111: in function 'handler'
miniloader/lualib/event.lua:15: in function <miniloader/lualib/event.lua:13>

Can you try v1.15.3?

For sure! I'll try when I'm off of work later tonight.

Working now! Thank you!