You downloaded a transcode. Someone converted a 128kbps YouTube rip to FLAC. The file size says FLAC, but the spectrum says MP3. Fix: Use Spek (Free software). Drag the FLAC into Spek. If the spectrogram cuts off sharply at 16kHz, it is a fake. Delete it.

It provides the quality of a CD (16-bit/44.1kHz) or better (High-Res 24-bit) at a significantly lower storage cost than raw formats.