The Samsung Tab S4 is a nice piece of hardware if you're into Android tablets, but it's very expensive. The new Tab S5e has some of the S4's features but drops the price to $400. It turns out it also drops the WiFi signal when you touch the corner. Maybe we're all just holding it wrong.
Based on reports from multiple users, the tablet's upper left corner (in portrait) needs to remain unobstructed to maintain WiFi performance. The Tab S5e is a large-ish 10.5-inch tablet with a widescreen ratio. So, it's a bit ungainly to hold in portrait orientation. However, in landscape, the aforementioned corner is where you'd naturally want to place your hand.
Users on Instagram have shown that WiFi connectivity can drop completely when touching the corner. Meanwhile, SamMobile has confirmed there's an issue by eliciting a 50% drop in signal strength when covering the corner. The issue brings to mind Apple's "you're holding it wrong" incident with the iPhone 4. Hopefully, Samsung's response is less aggravating, but a software fix seems unlikely. It may require a hardware revision to fix the signal issues.