Outlook on Mac running version Ventura 13.5.1 most pdf attachments disappear Outlook for Mac 16.76

I am having some strange issues running since last update with OS version 13.5.1 Ventura.  My pdf's usually disappear especially if I use attachment.  If I drag and drop they go through about 25% of time.  If I send other formats png etc. they go through about 80% of time. All are small format size 100kb give or take.  I have rebooted laptop and signed out of outlook with no luck.  Appreciate any help.