What happened
A shared browser may retain authenticated pages, saved form values, or downloaded screenshots after you leave. Closing a tab is not the same action as signing out. Ending CASECS2 access also does not prove that the related Steam browser session ended. Treat the machine as a separate account environment, particularly when different people use the same browser profile throughout the day.
What to check
Before changing a recipient, check the active account in both Steam and CASECS2. Avoid saving passwords on a public or borrowed machine. When finished, sign out of each service you used and revisit the account page to confirm that your authenticated view no longer opens. Remove personal downloaded evidence you created there. From a trusted device, review security if you suspect the shared computer was untrustworthy.
Worked example
For example, you copy a trade address in a gaming-room browser and then close the window. The next visitor restores the window and can still view your signed-in account. The problem is retained authentication, not the trade link’s format. Another mistake is downloading a support screenshot containing the token and leaving it in the shared downloads folder even after logging out.
Result and next step
Completion means the shared browser no longer opens your authenticated account and your private files are not left behind. If reporting suspicious access, include the approximate use time and device type without exposing other people’s data. Private browsing is not a guarantee against malicious software already on a computer. Read official Steam security advice; use CASECS2 guidance to separate site login from the Steam account session.