Different export time under the same conditions

I switch my PC on, wait for it to fully load, open Premiere Pro (2022.3.1), open my project, export it. The export time is 8-10 minutes. I open the exported video to check it, find a video editing mistake (a clip was improperly cut). Then I have to go out so I switch off my PC. When I return I again switch on my PC, wait for it to fully load, open Premiere Pro, open my project, correct the previously found mistake, export the project. The time of export is more than 40 minutes. 

Yesterday when I exported another project the time of export was 10 minutes but I deleted the video file by mistake and had to export again. I did not start any other programs, did't open Chrome to brows the internet and did not even play the music on my PC, did't do anything that could load my PC! Literally - I exported, deleted the exported file (by mistake) with Premiere pro still on, and exported again. The second time the export lasted 58 minutes. 

Can someone explain why this happens?