Hi. Tottally love Sparrow Solitaire and I agree with everyone that said this is the definitive solitaire mahjong version ever!
I think I found a bug on how the game computes the path in Shisen-Sho mode. I was able to spot it in the Phone layout. I have version 1.1. It didn't let me conect these pieces:
And surprisingly it did let me connect these, doing it by passing over tiles in the middle section:
Added the red lines just as reference of one possible path I was expecting it to consider.