I would not consider that normal. I have had mine linked for almost a year now without even a hint of wayward behavior. But, I am the only one using the Amazon and Wyze account. Are you sharing either the Alexa or Wyze with anyone else? A lot of times with other skills, sharing will confuse the skill credentials verification after the other person accesses the account under their credentials, thereby disconnecting or expiring yours.
Have you verified from the Wyze side that the Alexa link is listed and active in the Account tab>Smart Integrations?
If this is not the case, then I’ve got nothing. Perhaps others can provide insight: