Throughout the movie, Tanu has curly hair. Immediately after the marriage registrar-office scene, when she's washing her face, her hair have been straightened. The timeline does not match as the scenes in the movie timeline are not hours apart but just immediate after the registrar scene.
There is no direct train link between Kapurthala and Chandigarh. The one indirect link available now was not functional at the time of release. The rail link started functioning in late 2011.
When Manu Sharma goes to Raja Avasthi's house for the first time to see Raja's sister for marriage, Raja's father introduces another girl, Sapna, to Manu's father as Raja's fiancée. Sapna is never seen or mentioned again after that, but later Raja is seen trying to marry Tanu in a Court in Kapurthala. It should also be noted that Raja was the one to send 4-5 goons (via another friend Ravi Kishan) to scare Manu when he first reaches Kanpur Station. It is confusing because Raja is already engaged to be married to Sapna by then.