I was playing the GO battle league and I sent out my Lapras. The opponent used solar beam and I was like “alright he’s an ice type, that wont hurt him” but then the Grotle took out my whole Lapras. I immediately went to Google and it said the same thing, Lapras is weak to grass. How could this be if its primary type is ice and its secondary is water?! Shouldn’t it at least do normal damage or resistance?
Ice doesn't resist Grass
So Water/Ice is weak to Grass.
EDIT: Water is also Lapras's Primary type and Ice is it's Secondary type.
However, Grass is weak to Ice. This is what you are probably mixing it up with.