The word "sweet" is used in many contexts regarding wine and not all of them refer to sugar. During fermentation especially, your must is sweet. You will learn to taste around this, but it is also good to learn to recognize the declining sweetness that indicates the progression of your fermentation.
If your wine tastes sweeter than on a previous day, it may be your palate that caused the change or it may be indicative of a problem. If the WineCoach has not alerted you to any issue and/or the Brix is greater than 0°, then no action is needed. The perceived sweetness is likely just that: perceived. If the Brix is less than or equal to 0°, then test a sample with a hydrometer to confirm the Brix value.