In the season 2 finale of The Boys, Becca pierces a knife into Stormfront's eyes and the latter gets injured very easily. However, in previous episodes Stormfront is capable of withstanding Homelander's lasers. So, it doesn't make sense that Stormfront gets injured that easily with a knife. Was it a mistake or is it that Stormfront is not strong enough (and Homelander was maybe shooting laser with minimum intensity so as to not hurt Stormfront)?
Her body is capable of withstanding Homelander's lasers. We never see anyone attack her eyes. Up until that moment there was no indication that her eyes were more resilient than any normal humans.
Her eyes turned out to be her Achilles' heel. Becca had no reason to believe that stabbing Stormfront in the eyes would work, but at that moment it was her only option. She lucked out and it worked. Perhaps Stormfront herself didn't even know (how often is someone stabbed in the eye?).
This kind of weakness in Supes isn't without precedent. In the first season, Translucent was invulnerable in the outside, but his insides were seemingly normal. In Season 2, Black Noir is shown to withstand a lot of abuse, but he has a severe peanut allergy and was very easily put out of commission because of it. Frenchie in particular was very good finding and exploiting weaknesses in Supes which is what got him a spot on Grace Mallory's team.