A bigger issue is the 'left-right' spectrum. It's nonsensical, obsolete, undefined, arbitrary destructive garbage that does nothing but encourage false conclusions. And guess what, liberals were by definition originally part of the left wing. Basically all the people who didn't want a monarchy were. Since then, the left-right axis was never given any real meaningful definitions: we would have just used those words instead of irrelevant directions!
Introductory reading: https://en.wikipedia.org/wiki/Leftβright_political_spectrum
A useful video and discussion of alternatives: Why The Political Compass is Wrong: Establishing An Accurate Model of Political Ideology
Any one who is claiming that the left is only socialists isn't even wrong. The whole concept of 'left' makes no sense.
Regardless, someone saying that liberal is left probably hasn't been exposed to the socialist left. A possible opportunity, or simply a red flag to avoid. Use your judgement.