Disappearing contacts in iPhone AND iCloud. IOS 14.8

Cards regularly go missing from Contacts on my iPhone SE (current model). They are also missing from my iCloud account. But they remain in Contacts on my MBP.

Synching, resetting or rebooting doesn't help. The only work-around is sharing the card from the computer to the phone . Contacts missing on the phone are also missing on my 2 iPads and also have to be restored by sharing the contacts from the MBP.

A major problem because I never know what's missing until I need it.

Grateful for any insights.