Duplicate O word label error in version 2.6

There is no error if I don't edit the file.

The error will occur once for every change (inserting blank lines before o100). The second time I call the subroutine the error does not occur.

The error also does not occur if I toggle the e-stop and machine power buttons:
- machine is on
- edit file to add blank line to move o100 if line
- toggle e-stop and power
- call subroutine
- no error

This sounds like a problem with cacheing. I think that the interpreter might load a copy of the subroutine file, and it gets confused if you edit the file while the system is live.

I think this is strange, and incovenient, but probably not a major issue for most installations?

I suppose it's something to be aware of. In my case I was making frequent edits to the subroutine and calling it again. Now I know to toggle power or call the subroutine two times ignoring the error on the first call after the edit.

I wonder if this was the cause of the problem with the OP. They don't mention if the file was edited with the machine on. Even simply adding a comment line could trigger this error. The first call would be OK then adding a comment or some other edit could trigger the error on the second call.

I think it is worth raising a bug tracker for this, it looks like some check is flagging a false positive.
Can you confirm what version of LinuxCNC you are using? The OP says 2.6 but it is an old thread.

I'm using 2.8.0~pre1 from March 19 2018.

github.com/LinuxCNC/linuxcnc/issues/455