I see this a lot during several hours (until dark) after the water change, but never subsequent to that.
It is harmless.
"Pearling" is oxygen bubbling from the leaves as a result of very fast photosynthesis. Those who diffuse CO2 into their tanks frequently see this, if the light and other nutrients are balanced. One botanist told me I saw it after a water change because of the excess CO2 in the tap water.