In Windows, when you put the computer into standby while it is using a connection, the computer goes into standby before the dial-up connection can be completely disconnected. Therefore, the disconnection process is complete only after the computer resumes from standby
Ie. nothing to worry about
Don't be frightened into downloading a dodgy reg cleaner that may do more harm than good.
The Registry tool in CCleaner is the only one I recommend as it doesn't do any harm and is the safest I know after using several over the years
Click on Registry Scan for issues - Fix selected issues - Fix all issues
do this a few times until it sops finding anything.