Hello,
I have a Summarit, a M 6 and a IIIf. On the IIIf the Summarit is perfectly aligned with the index at the 12 o'clock position. Then I tried it with three different original made by Leitz Wetzlar LTM to M-adapters (for 50 mm, 90 mm and 135 mm) on my M 6. Result: With all three adapters the Summarit on the M 6 is exactly as misaligned by about 45° as on your photos. So your Voigtländer adapter and you Summarit seem to be o.k.