Some technical reasons :
1. Surface is sloppy. (Flat & hard surface is recommended)
2. 4 electrodes will work when the same amount of force is applied to them. If weight is not equally balanced on all electrodes then data won't be accurate.
3. Do not shake your body while measuring.
Daily weight fluctuation is normal.
The average adult weight fluctuates up to 5 or 6 pounds per day. It all comes down to what and when you eat, drink, exercise, and even sleep. It is usually the result of food or water intake. Eating a healthy, balanced diet on par with the number of calories your body uses daily may reduce your chances of significant weight fluctuation over time. But it can be a challenge to eat and drink in moderation every day. If your diet has been slipping, you may notice more weight fluctuation.
Sodium and Carbs cause water retention.
Food high in salt and carbohydrates may cause your body to retain water. Your weight may spike until the bloat subsides. Exercise Expending energy by burning calories can result in weight loss. But if you’re adequately hydrating, you may not see immediate weight loss on the scale. That’s because the water you drink replaces the water you’ve lost via sweat. Water, however, contains no calories and won’t cause weight gain over time.
Exercise burns calories, so if you burn more calories than you eat and drink, you will lose weight.
Medication
Some medications cause your body to retain water, increase your appetite, or change your metabolism. If you think your medication is affecting your weight, make an appointment with the prescribing doctor. They can help you determine the reason for the fluctuation and discuss your options moving forward. This may mean switching medications or making dietary and fitness changes.
Menstrual cycle
Your menstrual cycle can cause your body to retain more water during certain times of the month, resulting in a slight weight gain. You may notice that your base weight is a bit higher than normal on the first day of your period. Your daily weight should go back to average within a few days of your cycle beginning.
Alcohol intake
Alcohol isn’t processed the same way as other beverages and foods, so it can take longer for your body to eliminate. It also slows the digestion of other substances, which can lead to water retention. Beyond that, alcohol contains extra calories that you may not be accounted for in your overall diet.
Electrodes are getting stiff 4 electrodes will work when the same amount of force is applied to them. If weight is not equally balanced on all electrodes then data won't be accurate. Due to stiff support block weight fluctuations occur more frequently.