I am using TexStudio 2.12.22 under Windows 10 on a computer with dual Xeon processors, 2.8 GHz, 10 cores, with 64 GB RAM. It is often slow to respond when I type in the editor, and frequently drops characters when I type quickly. I do not see this behavior when I type quickly in any other application.
To reliably have all the characters I type appear in the TeXStudio editor, I have to type very slowly (only a few characters per second).
For example, if I quickly type, "This is an example paragraph that I am typing quickly in TeXStudio", this is what appears: "Thiss n example aragraph tha I amtypig quckly in TeXStuio."