Contacts changing to numbers and disappearing

[cbaillie72]

Help.
Some of my contacts keep slowly disappearing. I contacted apple support and did a full IOS install. It still keeps happening.
Any information would be great
Thanks

 

[jpn]

i have experienced this as well (this meaning: the name of the Contact changing to all numbers).
but for only a day or two, and only on a couple of Contacts.
the ones that were affected on my mac (macOS High Sierra), were contacts that were newly made and which were also containing Vietnamese fonts and accent marks in the Contact name fields.
i needed to delete them and remake them.
but it was ok the 2nd time, even with Vietnamese fonts/accent marks.
i wondered if during the 1st time it sync-ed over iCloud (i have Contacts set to sync over iCloud) something happened that scrambled the non-Ascii characters.