It's pretty obvious other teams know Levi is weak in coverage & tackling. They try to isolate him on one side of the field so a good RB can bust around or through him.
The NFL Scouting report on Levi prior to the draft:
Levi Wallace has had a very productive college career. He has played in high pressures situations and performed well. However, his lack of size will cause him to fall when the 2018 NFL Draft rolls around in April.
Wallace not only lacks ideal height, but also has a tiny frame. The lack of bulk will cause some durability concerns as well as issues dealing with more physical wide receivers and RB's..