that usually happens if the part is really small - or the measurements are in inches (slicers pretty much only understand millimetres.)
For some reason the slicer will increase the size to around 2225%

All you need to do is to go into the resize tab and put it back to 100%.

In flashprint you select the model and open the SCALE menu on the left side of the screen.
Set it to 100% and that should sort it.