That happens to my wife's Z2 Play all the time when the internal storage is close to being full. Sometimes it takes a good 5 - 10 minutes for that screen to populate
Quite a few more people have posted on the Moto Forum with this issue. Some have their Call History list clear every day and others have their Favorites / Started Contact list clear frequently. There doesn't seem to be a common factor yet, multiple different phones on different carriers. There has to be a reason for this, but that reason is currently unknown
For the first time since my problem started my frequently called numbers were not wiped out last night. This is getting stranger every day.
That is very possible. I just checked my phone and all Google sync options are On. Maybe that's why my call lists have not cleared?
I have same problem with my Moto G5 plus. Tried all the things mentioned in this thread. Started happening about a week ago. Still have the problem.