Breakthroughs when signatures go down?

I confess to be a little thrown by this but i’ve a couple on instances when I’ve recorded a breakthrough yet all fitness signature values have dropped slightly? Is this correct?

Near breakthrough

all three dropped and its a breakthrough not fakethrough - am I missing something? Xert

Did you change your Decay Method?

Breakthroughs are based on signature decay. If you switch to a method with less decay, you may lose a breakthrough. You may also want to update your time constants from 42/7 to 60/5, 22/12, 22./12 for low, high and peak under Account Settings. This could also affect breakthrough signature changes.

I did change to slower to try and reduce breakthroughs. Ok thanks for advice will investigate.