I doubt it... unless you left the print in the fixer for hours, the silver bleaching shouldn't be much. I suspect more like inadequate exposure, or negative's contrast being too high. With liquid emulsion, it's not hard to coat too much emulsion and think it's a fast emulsion.
Also, the speed of emulsion changes depending on how well the material is dried. So, if you test expose with one condition and final print at another, you may be introducing a source of error there.