You are likely referring to is seeing multiple 100% changes in your 'What Caused This' analysis. And while there are probably instances where your key Measure does a perfect 2x and increases 100% compared to your comparison period, it is highly unlikely that it would occur this often.
Instead what you are seeing in the above screenshot, is a bunch of 100% changes because those customer data points, did NOT exist in the comparison period. The data of the time period of focus cannot be compared, if there is nothing to compare it to, so instead by default Auto Insights shows 100% change.
An easy way to check if this is the case is to look at the Total Amount and the Change Amount. If 'Total Amount' == 'Change Amount' that is a signal that that specific data point, did not exist in the comparison period.