One useful thing I learned about digital scales is that if they are battery powered and start behaving more oddly than normal, change the battery to a known fresh one no matter how the present one tests.
320090T- I suspect both you and I know who makes the RCBS digital scale. They do change the color and print RCBS on the scales and raise the price a little. I must smile when someone states that PACT scales are not good and RCBS scales are very good.
My PACT scale has worked well, I have never seen a PAC scale.
Pact makes for RCBS and who else???
In regards to your scale problem. Is there a breeze hitting the scale?
Next is the electric in your home or apt. The pact is very sensitive, if the outlet your using is for ex, on the same line as the fridge, when the motor on the fridge goes on this can change the readout for a bit. The only way to check it is to use batteries, if by doing this the read out is constant with no change you must use bats only or find or install a dedicated line.
This is just a suggestion, but try sitting the unit on "dryer sheet" when in use. My transformer powered PACT doesn't like static electricity (which this helps)but otherwise it has been remarkable. Good luck.
I've had a handful of electronic scales go "bad" over the years. the newer ones are a little better, but I don't have as much faith in them as I would a balance beam. Even the lowly LEE scale might be more reliable. Granted, the electronic scale may be faster in some cases, but I use the balance for the vast majority of my needs.