Yes. In DA3.0, WW introduced these warnings as well as a cleanup routine to remove strands when FPS drops. As I understand it, it's not so much that DA3.0 is causing your FPS to drop, but rather telling you it is low and that it is cleaning things up to improve it. The reason for this is that many DA commands will fail to be recognized when FPS is low, so he wanted a cleaning routine to avoid this and keep dialogues and the game running smoothly. (WW believed causing the strands to display dynamically and react to the game's progression is very computationally intensive. Thus when FPS drops he tries to clean them up to free up computer resources and increase FPS. Of course it's possible you have other causes for your drop in FPS that he is not addressing with this method.)
To avoid this issue, I believe sby has some mods which allow you to control the number of strands of various substances. You might be able to use these mods to reduce the number, duration or complexity of strands if they are interfering with your FPS.
In short, DA3.0 is not causing your FPS to drop; it's just telling you that it has dropped and that it's trying to take some steps to correct the issue. Or at least that's my understanding.