Bug with calculations? Variable names influence result?

I found a weird bug while trying out some very basic calculations for IV fluid solutions…
Basically, the variable name seems to influence the results of the calculations. See image for examples.

For example, Phos (20) x volume (0.56) = 11.2 (correct).
But PO4 (20) * volume (0.56) = 235.2!!!

And PO3 (20) * volume (0.56) = 179.2 (+56 vs. PO2)
PO2(20) * volume (0.56) = 123.2 (+56 vs. PO1)
PO1 (20) * volume (0.56) = 67.2 (+56 vs. PO0)
PO0 (20) * volume (0.56) = 11.2 (correct)

Interestingly, PO4 (20) * 0.56 = 11.2 (correct)

So it looks like the calc operator interpret two terms and then adds then up
For example, PO3 (20) * volume (0.56) = 179.2
is (20 * 0.56) + (3 * 56).

Am I doing something wrong? Is this a known bug with java-based calculations?

Screen Shot 2020-12-14 at 9.47.35 AM