I have a LG G6 phone running Android 9. My primary contact source is Google contacts. I synchronize my phone contacts with Google. Once in a while, some contacts seem to disappear on my phone but they are still there on Google as seen on my PC. The name of the contact is no longer there but the contact information is picked up by another contact, including the associated picture. This contact may collect the data for many "disappeared" contacts. This seem to happen only with contacts that have pictures. It seems that most of the pictures can be associated with Facebook friends but some have unknown origin. I don't use other social media apps, just FB and, sometime, Messenger.
I can easily recover my contacts by deleting them on the phone, syncing with Google (they also disappear there, including those that have disappeared on the phone), restoring the contacts to a past version on Google and syncing the phone.
At least, I don't lose anything but it is very frustrating when I am not at home and need a number that I want to use. I don't have the time to search my 250+ contacts to find where the number went.
Please note that I have seen mentions of this or similar problems dating back to 2010.
I can easily recover my contacts by deleting them on the phone, syncing with Google (they also disappear there, including those that have disappeared on the phone), restoring the contacts to a past version on Google and syncing the phone.
At least, I don't lose anything but it is very frustrating when I am not at home and need a number that I want to use. I don't have the time to search my 250+ contacts to find where the number went.
Please note that I have seen mentions of this or similar problems dating back to 2010.