It is widely reported that the IG found there was no evidence of political bias - but it is also not what he said, in either report, though his HR-specific phrasing lends itself to be mischaracterized that way.
In the previous report, he said he found no *direct* evidence of bias, which is explained a *bit* more clearly in the FISA report: He found no *documentary* or *testimonial* evidence of political bias. All that means is the no one wrote about their bias and asserted it was due to political cause, nor confessed to such. The IG does not at all assert there was not political bias, and simply does not speculate on the cause or source of the clearly biased actions which he documents all over the place.
One really shouldnt expect for there to be those things regardless of whether or not there was political bias.
To me, the very least description of that this shows is comparable to a ship run aground on clearly charted reefs and having its hull shredded while the Captain and his officers are asleep in their cabins and the ship’s cook is on the bridge manning the helm.