How Do I Adjust Modification Dates In Properties?

I am using 20.04.1, and when I check the modification dates in Properties after saving my files, the dates are incorrect, usually with dates occurring in the next 2 or 3 years listed (2021 to 2023, sometimes 2025). I want to correct this problem; is there a way to do that? Two screenshots below:

One more thing that I have noticed: some of the regular folders are showing advance dates, too!
This seems to be a widespread problem affecting many files. The highlighted files are being stored on a Western Digital Passport 250 GB drive. Can someone help me? Thank you.

Have seen the issue. Have 3-2tb. Seagates for backup. I copy all my changes to a folder and at interval connect to the drives and backup to various locations. Two show newer file exists even though I know the backup is newer so just let it overwrite. Have checked and the file is correct except for the date. Other drive says older version correctly. Noticed before 20.04 and kinda ignored it as I know my files are newer. Lately checked and did not find a definitive answer on the web for the issue. Seems Windows also has similar problem. Sorry for no answer.

Mendy, thank you for the insight. Maybe the developers or geeks can conduct experiments using different external drives and op systems to duplicate and troubleshoot the scenarios we have presented here. This is truly a strange situation we have going on; I believe if this is happening to us, it's probably happening to other users. You gave me an answer, you did well.