If you could send a project that reproduces the issue, that would be helpful.
In any case, if you are always going to save text content in the blob field, add the attribute DBTypeMemo (or DBTypeWideMemo) to your mapping so Aurelius knows it's a memo field:
[DBTypeMemo]
[Column('logo', [TColumnProp.Lazy])]
Flogo: TBlob;
In the dataset, also try to treat it as a memo (or widememo) field.