vertical jigsawblocks generation

is there a way that you guys know about to make vertical jigsawblocks to generate their targets more reliably? i have this layout with upwards facing jigsaw blocks that spawn the road pieces https://i.imgur.com/xUDo1pK.jpeg but ingame it often refuses to place the roads even tho they work sometimes https://i.imgur.com/96j9Em4.jpeg (pink wool and other odd blocks are debug and tests )