That was one one very small part of a large and complex investigation, and frankly it was a thread that ended up not going anywhere useful, stop acting like it was some kind of linchpin for the whole thing. The findings of Mueller, and especially the Senate Intel Committee, are solid and damning. The only open question at this point is whether or not Trump knew what was going on with the contacts we now know happened between Russian agents and his campaign manager, personal attorney, son, daughter, son in law, longtime fixer, etc...
Do you know what that supposed lie you are hanging your hat on was, by the way? Clinesmith (the CIA lawyer) wrote into an email used for a warrant re-up (not the original warrant) that Carter Page was a CIA "subsource, not a source". Hardly material or relevant at all to the overall findings. They went over the whole series of investigations with a fine toothed comb, multiple times, only coming up with that and got a 6 months of probation sentence to show for it, before Durham's embarrassment if a probe ended up fizzling out with two trial aquittals.