George,
Yes, his CSR does show some inconsistent record slips.

12 May 1864 POW Spotsylvania CH
18 May 1864 Received at Pt. Lookout MD from Belle Plain VA
28 May 1864 Released from Pt. Lookout, joined US Army
30 July 1864 Transferred to Elmira NY [?]
2 August 1864 Received at Elmira [?]
27 June 1865 Took oath & released [?]

Wonder who may have been the man who was transferred to and held at Elmira until June 1865? Or was it just a paperwork error?