From v18 https://www.ag-grid.com/ag-grid-changelog/ ag-grid uses flex to do the layout
Unfortunately, this doesn't make us compatible with Safari 10 given they have quite a buggy implementation of flex
This was a hard decision to make, but the overall wins in terms of simplifying our code, and hence allow us to deliver more features made it us decide to go forward.
When we looked at this, we looked at the market share of Safari 10
Based on this data, we understand that there is going to be a small number of customers affected. Our recommendation is to either update your clients if possible or if not possible to keep using ag-grid v17.1.1