the following code in my mod:

if remote.interfaces["picker-dollies"] and remote.interfaces["picker-dollies"]["dolly_moved_entity_id"] then
script.on_event(remote.call("picker-dollies", "dolly_moved_entity_id"), picker_dolly_move)
end

produces the following error in yours:

Error while running event wret-beacon-rebalance-mod::on_load()
Error when running interface function picker-dollies.dolly_moved_entity_id: even-pickier-dollies/interface.lua:34: attempt to index upvalue 'epd' (a number value)
stack traceback:
even-pickier-dollies/interface.lua:34: in function <even-pickier-dollies/interface.lua:33>
stack traceback:
[C]: in function 'call'
wret-beacon-rebalance-mod/control.lua:127: in function <wret-beacon-rebalance-mod/control.lua:121>

thanks. That is a bug that crept in when I was removing the stdlib code. Will fix it and push a new release.

it is fixed in the 2.0.1 release. I tested it with another of my modules that also register with the dollies.

it appears to be fixed now. thank you.