LRC attempting to synch ghost images (ie from synch with previous computer)

[Onag]

I am running the most recent versions of LRC and Lightroom (mobile) on a Mac Pro under Catalina.  I keep everything autoupdated.  I synch some collections between LRC and my iPad and iPhone.  I am aware you can only synch between one LRC catalogue.  LRC is persistently trying to synch 23 images from an old catalogue.  In the past, during travel, I stopped synching between my desktop and the devices and synched instead btween my laptop and devices.  However, even though I have switched back to my desktop. LR is trying to synch 23 images from the old laptop.  I can see that by looking at the Synch window in LRC/preferences.  I tried rebuilding the data by Option clicking on Delete All Synched Data but it is still happening.  It causes problems on exiting the program and may be causing other difficulty as well.  Any other thoughts on how to make this stop?

[cmgap]

When you log in to lightroom.adobe.com do you see sync errors in the left column? If you do see them - delete them here and the problem should go away.