She and her disciple have bene deducing something all of these years. It is one of the reason why Will the Golden Speedsters is rarely seen in public anymore
After deducing countless of possibilities, both she and her disciple reached the conclusion that the memories that she had lost is not because of trauma but maybe because she herself had removed those memories from her mind.
It is something that seems farfetched but she knows this is a method used by many beings.
She is also included in those list of beings who would remove a memory from her own mind if there is a compelling reason to do so
There is only a few reason why a being like her would remove her own memories, her own powers and abilities
One of them is to avoid being entangled in some cause and effect. The other is because the memory is hindering her. Or the memory is something that is so painful that she had to remove it.