What you should infer is that an unforeseen result was produced because the original regular expression `"CPU\(s\):|Thread"' was able to match the following line, outputted by lscpu:

Code:

NUMA node0 CPU(s):     0,1

This is correct since it satisfies the regex by matching the part CPU(s):
In order to exclude that unwanted match, the beginning of line anchor was added later on.

Code:

"^CPU\(s\):|Thread"

Letting only match like these be the acceptable result:

Code:

CPU(s):                x
Thread(s) per core:    x

Even when, maybe, just in case, it should be

Code:

"^CPU\(s\):|^Thread"

if the lesson was learned.