Different op.system without all documents.

[sabicammar73-create]

Describe the bug
A clear and concise description of what the bug is.

Note that any how to questions should be posted in the discussion board and not raised as an issue.

Version of yq: 4.X.X
Operating system: mac/linux/windows/....
Installed via: docker/binary release/homebrew/snap/...

Input Yaml
Concise yaml document(s) (as simple as possible to show the bug, please keep it to 10 lines or less)
data1.yml:

this: should really work

data2.yml:

but: it strangely didn't

Command
The command you ran:

yq eval-all 'select(fileIndex==0) | .a.b.c' data1.yml data2.yml

Actual behaviour

cat: meow

Expected behaviour

this: should really work
but: it strangely didn't

Additional context
Add any other context about the problem here.