When I try to blueprint a station that includes either the loader or the unloader using the shortcut Alt+B I get this error:

The mod Bulk Rail Loader (1.1.6) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event railloader::on_player_setup_blueprint (ID 70)
LuaItemStack API call when LuaItemStack was invalid for read.
stack traceback:
[C]: in function 'get_blueprint_entities'
railloader/control.lua:339: in function <railloader/control.lua:335>

I can use Ctrl+C/V though.
Let me know if you need more information.

Can you explain the exact sequence of steps and also provide a save or a modlist?

Hi, sorry for the delay!

Here's my mod list:

Aircraft = "1.8.4",
AircraftRealism = "1.4.1",
AutoDeconstruct = "0.3.3",
BlueprintLab_design = "1.0.3",
BottleneckLite = "1.2.4",
CleanedConcrete = "1.0.2",
Companion_Drones = "1.0.24",
["Constructron-Continued"] = "1.0.33",
EditorExtensions = "1.13.4",
FluidMustFlow = "1.3.1",
HallOfFame = "1.14.0",
Krastorio2 = "1.3.4",
Krastorio2Assets = "1.2.0",
LTN_Combinator_Modernized = "1.0.11",
Landfill_plus = "1.0.19",
LogisticRequestManager = "1.1.23",
LogisticTrainNetwork = "1.16.10",
LtnManager = "0.4.15",
Milestones = "1.3.7",
ModuleInserter = "5.2.4",
Noxys_Waterfill = "0.4.4",
OreEraser = "1.5.6",
["OutpostPlanner1-1"] = "1.2.3",
["PlannerCore1-1"] = "0.3.2",
RateCalculator = "2.4.4",
RecipeBook = "3.4.5",
StoneWaterWell = "1.20.1",
TimeTools = "2.1.44",
["Todo-List"] = "19.2.0",
VehicleSnap = "1.18.4",
WellPlanner = "1.1.0",
WireShortcuts = "1.1.9",
["aai-containers"] = "0.2.11",
["aai-industry"] = "0.5.19",
["aai-signal-transmission"] = "0.4.7",
["alien-biomes"] = "0.6.7",
base = "1.1.68",
bobinserters = "1.1.5",
["bullet-trails"] = "0.6.2",
["emoji-signals"] = "0.2.0",
["equipment-gantry"] = "0.1.5",
["even-distribution"] = "1.0.10",
factoryplanner = "1.1.51",
["far-reach"] = "1.1.2",
["faster-robots"] = "0.0.2",
flib = "0.10.1",
["grappling-gun"] = "0.3.2",
inbuilt_lighting = "20.1.11",
informatron = "0.2.3",
jetpack = "0.3.5",
["logtech-beacon"] = "1.2.1",
more_circuit_signals_UPDATED = "1.2.1",
["nixie-tubes"] = "1.1.3",
["power-grid-comb"] = "1.1.0",
railloader = "1.1.6",
resourceMarker = "0.7.28",
robot_attrition = "0.5.12",
["rocket-log"] = "1.1.9",
["shield-projector"] = "0.1.6",
simhelper = "1.1.4",
["solar-calc"] = "0.3.11",
["space-exploration"] = "0.6.85",
["space-exploration-graphics"] = "0.6.11",
["space-exploration-graphics-2"] = "0.6.1",
["space-exploration-graphics-3"] = "0.6.1",
["space-exploration-graphics-4"] = "0.6.2",
["space-exploration-graphics-5"] = "0.6.1",
["space-exploration-menu-simulations"] = "0.6.8",
["space-exploration-postprocess"] = "0.6.18",

And the exact sequence of steps was:
- open the editor
- open the blueprint library and grab a station bp than included BRLs
- stamp it down
- try to blueprint it again using the Alt+B shortcut
- crash
It also happened when I tried blueprinting a station that was already on the map.

Obviously, it didn't use to happen before, given that I had blueprints with BRLs in my bp library. And now it's not happening any more, but I hope this is useful to you in some way. Thanks for the quick reply and the great mod!

Same here but in creative mode:
Die Mod Bulk Rail Loader (1.1.6) hat einen Fehler verursacht, der nicht behoben werden kann.
Bitte informiere den Autor der Mod über diesen Fehler.

Error while running event railloader::on_player_setup_blueprint (ID 70)
Item is not blueprint.
stack traceback:
[C]: in function 'get_blueprint_entities'
railloader/control.lua:339: in function <railloader/control.lua:335>

Sequence:
- just pressed CTRL + C and draged a box even without a bulk rail loader in the box

Mod list:
BottleneckLite = "1.2.4",
Fill4Me = "0.10.0",
LTN_Combinator_Modernized = "1.0.13",
LogisticTrainNetwork = "1.16.10",
Warehousing = "0.5.6",
["aai-containers"] = "0.2.11",
["aai-industry"] = "0.5.19",
["aai-signal-transmission"] = "0.4.7",
["alien-biomes"] = "0.6.7",
base = "1.1.69",
bobinserters = "1.1.5",
["creative-mod"] = "1.8.0",
["even-distribution"] = "1.0.10",
flib = "0.11.1",
informatron = "0.2.3",
jetpack = "0.3.5",
miniloader = "1.15.6",
railloader = "1.1.6",
robot_attrition = "0.5.12",
["shield-projector"] = "0.1.6",
simhelper = "1.1.4",
["space-exploration"] = "0.6.86",
["space-exploration-graphics"] = "0.6.12",
["space-exploration-graphics-2"] = "0.6.1",
["space-exploration-graphics-3"] = "0.6.1",
["space-exploration-graphics-4"] = "0.6.2",
["space-exploration-graphics-5"] = "0.6.1",
["space-exploration-menu-simulations"] = "0.6.8",
["space-exploration-postprocess"] = "0.6.18"

Also the deconstruction time is too short. If you go manually to a station with a bulk rail loader and try to put the locomotive back in the pocket, it can easely happen that you deconstruct the loader together with the train by mistake.

Getting this same error in creative mode with map editor open (which is required - with the editor closed the error does not happen). To reproduce, load this attached save file, hit Ctrl-C to start copy, and select (at least) the top left part of the rail block the game loads centered on (other places may do it too - haven't tried).

Save file is at https://file.io/ppwo2AoafWo8

Getting the same error in map editor, was creating blueprints of rails, rail signals, miniloaders, small warehouses, stations. Didn't even place any bulk loader.

Using Nullius Momenti modpack.