Catalina's Finder Preferences weird behavior. See the screenshot

Dear Sharhari, thank you so much for your advice, it worked perfectly. I followed step by step what you advised and now my checked Karel's iMac drive still checked. At least I solved one of my problems, the other one is with my Google Drive for Desktop. My finder doesn't search inside that specific folder, but this is another threat that I already posted yesterday. Thank you so much for your help.