My M&M account now shows "xxxxxx award miles expire on 31.12.2018". The xxxxx matches miles I earned from my USA Barclays Miles & More World Elite MasterCard 36 months ago. I have had credit card transactions resulting in M&M miles added each and every month for 36+ months. The T&C says that should prevent expiration, so I sent an email form request asking why my miles are scheduled to expire. I got a quick autoreply with incident number, but I read in another thread another FT'er said no response after 2 weeks. So I will call M&M today. Backup plan is to book an award ticket 12 months out, but they really should honor their T&C!

Regarding miles tracking, the Account Statement shows most recent 3 months activity. At the bottom, you can click of Account History to show 4 to 15 months back. Both now show the miles expiring. Prior to 36 months of miles history, neither the Account Statement nor the Account History showed the miles expiring.