I called Citibank on Monday. They manage the TSM ADR shares and the person I spoke with said they had not received any info from TSM on when the ex/record date will be. When TSM makes the decision, Citibank is notified immediately. I'll be checking back with them in the next few days.
The record date from last year was June 15th, so based on last years date, the official announcement should be coming shortly.