It means that it was carefully tailored to be what the campaign that hired them wanted it to be.
So while it does not prove that it is fake, it certainly proves that it is not a credible source.
But don't take my word for it. Here's
what the FISA Courts said:
“The FBI’s handling of the Carter Page applications, as portrayed in the [Office of the inspector general] report, was antithetical to the heightened duty of candor described above. The frequency with which representations made by FBI personnel turned out to be unsupported or contradicted by information in their possession, and with which they withheld information detrimental to their case, calls into question whether information contained in other FBI applications is reliable,” federal Judge Rosemary Collyer wrote in an order from the court published Tuesday.