What size batch do you have currently residing in what size fermenter?
Vinegar notes are typically formed by acetobacter (bacteria) that grow in presence of oxygen and produce acetic acid. This acid does sour the beer but can easily overpower the more gentle lactic acid desired in these beer styles.
If you have a big headspace above the beer and did not purge your fermenter with CO2 prior and after racking, then this could be your culprit. As stated above, depending on its intensity, your beer could be a dumper. A little acetic acid is perfectly fine in some sour styles (Flanders Red, gueuze), but not all. And BTW, as the batch ages they typically tend to become more acetic as more oxygen ingresses over time.