Troubleshooting
A tester "dropping out" means they stopped actively using your app partway through the test — uninstalled, or just went quiet. It happens; it's also exactly why every Testers14 plan ships more testers than the 12-tester Google minimum — Starter's 15, Professional's 20, Max Coverage's 25 — so one dropout doesn't put your opted-in count at risk of falling below what Google actually checks.
Replacing an inactive tester is part of the service, not an extra step for you to take — no action needed on your end. What matters is that you still have at least 12 testers who have stayed opted in continuously, which is why every plan ships a buffer above the minimum. Be aware that a replacement starts their own 14-day continuous period and cannot inherit the days of the tester they replace — Google's requirement is worded per tester. Play Console remains the authoritative tracker.
Where it's worth a support ticket rather than waiting: if your dashboard's active-tester count looks lower than your plan's count for several days running, not just a one-day dip. A single day's dip is normal churn; a sustained one is worth us looking into directly.