When I had this problem with my t-pro I found that it was because the Monty snail cams were to small and didn't reach the bolt enough at first, so when it did touch, you didn't have enough of the snail cam left to tension. You can buy bigger snail cams, Like Viz or the Zhi ones, They are really big and will offer a lot of space to touch the bolt and pull the wheel back further. You could also just buy some new chain tugs, but the Allen key one's, Not the spanner ones. They Allen key ones, you can tension the wheel fine, Tighten the bolts up, and then just nip the bolts up so it stays tight. Also do the Hub bolts up as tight as you can, they can take a lot of pressure before they snap, so don't be worried.