The vertical space before the chapter title becomes increased after updating from MikTeX 2.9 to 20.6

Currently I’m using TeXstudio and configure it with MiKTeX 2.9. At first, nothing’s wrong with my document. But, somehow because I can’t use lipsum I tried to update the packages using MiKTeX console and finally there’s no problem with lipsum package.

Usually I need 9 seconds to compile my document (using TeXstudio), after the update I only needed 1 second even though my document was about 50 pages. I doubted at first, then I tried opening another document and it only took 1 second for that.

But there is a message telling me there is a crash with PdfLaTeX. Innocently, I deleted pdflatex.tex on package repository miktexbinx64. I thought I could reinstall it via the MiKTeX console. And that’s where many errors arise. So I uninstalled MiKTeX 2.9 and installed MiKTeX 20.6 (I think that the higher the version, the better the performance even though it sounds really stupid).

After install and such, I tried to compile my document, but the vertical space before the chapter titles on: ToC title, LoT title, LoF title, frontmatter chapter title, and mainmatter chapter title, all of them increased to about 20 pt. But it has no effect on the pages after the chapter. (This extra vertical line doesn’t exist in MiKTeX 2.9). Besides, the compile speed is back to 9 seconds.

So, what happened here? I want those vertical lines to disappear. I’ve checked the titlespacing titlespacing*{chapter}{0pt}{0pt}{20pt}. And I didn’t change it before I installed the new version, so the extra vertical line shouldn’t be there. And if it’s possible, I want the compile speed to be 1 second like when I update the packages.