Milwaukee pH Meter - Help!

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not normal, probe failing, battery ok?

I leave my probe in a container that reactor effluent drips into. When I turn the meter on, see the numbers bounce a bit but become steady after about 2 second. If I move my probe into the sump, it locks into the tanks pH in about 15 second with me not moving the probe around.

Using a Milwaukee meter, Aqua-digital probe.