kerndt I’dalmost certainly say yes the Citric Acid not being encapsulated, even in that small amount, was the cause of your issue. Acid breaks down the bonds in your meat and refuses to allow it to hold together. So, it can’t hold together to prevent rendering, but the proteins also cant hold water when their pH has been decreased, this is why we add Cold Phosphate - Sodium Phosphate to meat we want to be more juicy, because an increase in pH shifts the isoelectric point and allows the meat to bond to water. When it is low, it can’t do that, so most/all of the water wasn’t bound up in the meat.
While 20 mg does sound like a very small amount, the symptoms you are describing are exactly what I would expect to happen if someone ruptured the encapsulation on their citric acid.