Sample sizes are still quite low, but I think it is safe to say that Statikk Shiv is garbage on Zeri. Stormrazor into Runaans is probably the way to go, but there is not enough data yet to filter for specific build paths.
Yesterday I made a post about what I thought was a bug, but turns out I was misinformed. The description of her ult in-game is not as detailed as it is on League of Legends Wiki, but there is clearly says that the duration is not reset to 5 but increased by 1.5 seconds.
I Do still have a complaint though about what led to my misunderstanding: The remaining duration of the ult is visualized around the ult icon. The icon is surrounded by a full square at first, of which the line disappears over time. When you increase the remaining duration from let's say 1.5 to 3 seconds, my expectation would be that the line of the square increases from 30% to 60%. But instead it goes back to 100% and then just disappeas quicker in the following. Very unintuitive imo.
When you let your stacks of Overcharged expire, the remaining duration gets significantly shorter once you refresh it. This bug was already present on PBE and I reported it, but looks like they did not fix it. Maybe posting it here will will draw more attention.