According to Instacart Help Center on Tipping
Instacart suggests a default tip based on a number of factors, such as order attributes and your tip history. The minimum default tip is 5% of your order total.
Which it has been for some time. But my last few orders the default tip was 10%. If you are like me and you just automatically power through all the things they put in front of you on your way to complete your order, you might not even notice it.
There does not seem to be a way to change the percentage back. You have to do it manually each time you get an order.
If 10% is what you normally tipped anyway, then you are all set. If you want more flexibility over your tip, be advised.
Smart People I Know 