What Causes the Torque Sensor to Have Unstable Output Signals?

I bought one torque sensor and have used for one week. But now the torque sensor often encounters unstable output signals during use, but there is no problem after sending the sensor back to the manufacturer for testing. What is the reason? Did I use it in the wrong way?

How in the world are we to know how you might have used it?

Read the forum guidelines. Post code. Post schematic.
Use the IDE autoformat tool (ctrl-t or Tools, Auto format) before posting code in code tags.

You will have to define "unstable" in terms of actual numbers and the range of numbers that could be expected.

What are your expectations of "stability"?

Also specify what is on each end of the torque sensor.

And did you use it with a load cell transmitter or use something like the HX711?

We only have the information you give us, and the more information we have the more use we can be. Usually that means at least:

code

circuit

datasheets for each piece of hardware you use.

Should we assume you use the basic 4-20mA model, and a 5volt Arduino like the Uno.
Should we assume you use a 250 ohm sense resistor (which is wrong).

Please give use all the details following to the forum posting guidelines,
so we can give you the right answers.
Leo..