AT&T Executive Says Q3 Fiber ARPU Fell 4% Due To Introductory Pricing, Discounts For Bundled Wireless And Broadband Customers, And Growing Base Of Lower-ARPU Customers In Territories Acquired From Lumen; Expect Fiber ARPU Will Continue To Be Impacted By These Dynamics, Including During Q4; Q4 Adjusted EBITDA Also Impacted By Unfavorable Vendor Dispute Settlements Of ~$100M That Will Primarily Impact Our Legacy Segment