Hi Sudheer,

As per my knowledge, excess heat or high current or maybe the problem

Warm transfers, which do not involve the use of ice packs or stirring, can cause gels to undergo slight shrinkage or warping can lead to this effect is most prominently observed in the upper region of the gel, particularly where heavy markers are located. If the sponges or papers do not evenly fill the cassette, uneven pressure distribution occurs, resulting in higher pressure in certain areas. Consequently, proteins tend to migrate laterally in regions where compression is reduced, often at the top edge of the gel.

Best,

Subhajit