Interpreting the data is the tricky part. The poll shows that even if Horwath has the lead in the poll result, Doug Ford is still likely the winner by about 7:1. And that is for majority government.
The big change in numbers seems to have "flattened out" now, so presumably this was an adjustment, probably not any fault of Doug Ford. Doug Ford has not made any serious gaffs thus far. No embarrassing videos, no skeletons in the closet, and no Stormy Daniels have as yet been forthcoming. (And you better believe they're looking!)
Anyway the poll data shows she is not in the lead. Unless you only look at only the data. But, the poll does make assumptions about the data, in this case, how it is distributed among ridings, and by that it defines the probability of the winning result. A probability is not certainty...