Two controversies regarding the recording sessions:
1. Organist Al Kooper has repeatedly insisted in interviews that the Nashville recordings were completed within a single set of sessions spread over a week to ten days. He says he recalls making only one trip to Nashville, and that the claims of a second series of dates must have arisen from latter-day amateur researchers not understanding the studio logs. For example, an entry for an engineer running off an acetate of one of the songs could have been misinterpreted as a recording session.
It is difficult to understand how two trips from New York to Nashville could have been conflated in Kooper's memory into a single trip (or alternatively how a single trip of nearly a month could be remembered as lasting only a week to ten days). Nonetheless, plenty of other evidence does support the notion of two separate sets of sessions.
2. There is also some disagreement as to whether guitarist Robbie Robertson was present at the February recording sessions, or, if he was present, whether he actually played on any of the recordings made. According to Al Kooper, Robertson was in Nashville the whole time Kooper was there, but there is no mention of Robertson in Krogsgaard's documentation of the personnel for the February sessions. Moreover, Daryl Sanders, in his account of the sessions for Nashville Scene in 2011, makes no mention of Robertson in relation to the February dates but says: "When he returned in early March during another short break in his tour, he brought The Band's guitarist Robbie Robertson, who added a blues flavor to the six-string mix." And Barney Hoskyns, in his book about The Band, Across The Great Divide, says “Even Robbie took a backseat to guitarists Joe South and Wayne Moss, waiting till Dylan returned to the studio in early March to add his distinctively ratchety licks to the gritty blues of ‘Obviously 5 Believers’."
This, of course, raises the question of who played the unforgettable lead guitar part on "Visions Of Johanna", recorded at the first of the February sessions. It has always been widely assumed to be Robertson, and indeed for many listeners the sound of these lead guitar phrases has probably formed part their mental map of Robertson's style. But Daryl Sanders, in the article referred to above, states that the lead guitar was played by Nashville guitarist Wayne Moss, apparently on the basis of an interview with keyboard player Bill Aikins. Aikins was evidently present at the session, but is not audible on the released take of this song. Both Aikins and Moss appear on the documented personnel list for the session while Robertson, as indicated above, does not. Draw your own conclusions!
Robertson's 2016 autobiography, Testimony, while seeming at times to betray a somewhat shaky memory of events 50 years in the past, makes a convincing case that (1) there were indeed two sets of recording dates in Nashville, and (2) that Robertson was not present at the first set. So if that really is Robertson playing lead on "Visions Of Johanna", he must have dubbed it on later, most likely at the March sessions.