The unnamed developer from Bplus Games told GameSplash that only certain zoom ratios are affected. "Most of the frame-rate issues in Zelda are just programming failures. If Nintendo sets the right people to it they can totally fix them, " the developer is quoted as saying. "Some dev friends and I have the same feeling about that. Because sometimes it is just a specific zoom ratio that makes the frame-rate drop. Just zoom in a bit closer or further away and it runs super smooth. The problem is that the game wants to show both near and far LOD (Level of Detail) objects. This is a frame-rate killer if two objects are in each other. To show that, it would need around 10 times the power. And if you see Kakariko Village, the framerate hell there, and then the more beautiful Hateno Village, which runs super smoothly, you see that doesnt make sense. So something else is going wrong there."
The dev also said that Nintendo knows about the LOD issue, but hasn't fixed it yet. He explains that in his chats will some Nintendo developers, he found the game originally ran at 60fps, but they didn't want performance fluctuations, so they focused on capping it at 30fps.
The dev then went on to explain the difference between docked and undocked mode. "A lot of things change between docked mode for Switch, besides the resolution. The distance for LODs are changed, the types of texture filters, the distance of texture filters, levels of tri-linear mappings, etc. All depending on graphics. But for example, the zoom ratio of the LODs are changed, which is a coding part. That also would be the issue with the zoom level frame-rate issues. So yes, it is a programming issue in TV mode that doesnt relate to power."