The longest problem with two non-symmetrical solutions of the same length:
Cornel Pacurar & Arno Tüngler
1st Prize, Danish Chess Problem Society 61 TT, 2010

ser-sz b7 in 2016 moves
(Series-self-targetsquare b7)
2 solutions
Special Grid, PWC

= Wazir
1. WEf3-f4 2. WEf4*f5 [+bBf4] 3. WEf5-f6 …
65. WEf3*f4 [+bBf3] … 128. WEf2*f3 [+bBf2] …
…
1892. WEa7*a6 [+bBa7] … 1955. WEa8*a7 [+bBa8] …
2016. Web6-b7 Ba8*b7 z
1. WEf3-f2 2. WEf2-g2 ... 62. WEf6*f5 [+bBf6] 63. WEf5-f4 …
125. WEf7*f6 [+bBf7] … 188. WEf8*f7 [+bBf8] …
…
1952. Web8*b7 [+bBb8] …
2015. WEa8*b8 [+bBa8] 2016. Web8-b7 Ba8*b7 z
The theme of the tourney was Grid Chess and Rundlauf. In both solutions there are exactly 31 full rundlaufs (64 moves, covering each time all squares of the board), plus another one half rundlauf.