Quick answer: Watch for unexplained churn and bad reviews, a gap between problems experienced and reported, and crashes you can't reproduce. Most players who hit a bug never report it, so they hit bugs you can't see without field capture.
Your players are almost certainly hitting bugs you can't see, since most who hit a bug never report it. Here are the signs your players are hitting bugs you can't see.
Churn and Bad Reviews You Can't Explain
A sign is churn and negative reviews you can't explain by what you can see, players leaving or complaining about bugs and crashes while your visible data doesn't account for it. Unexplained technical churn and reviews point at bugs players are hitting that you can't see, driving the loss invisibly.
Bugnet captures crashes from the field, revealing the bugs behind the unexplained churn and reviews. Churn and bad reviews you can't explain are a sign players are hitting bugs you can't see, and capturing crashes from the field reveals those bugs (the cause behind the loss and complaints), turning the unexplained, the bugs you couldn't see, into visible, fixable problems.
A Gap Between Problems Experienced and Reported
A telling sign is a gap between how many players seem to hit problems (from churn, reviews, indirect signals) and how few actually report, since most players who hit a bug don't report. A large gap means players are hitting bugs they don't report, bugs you can't see if you rely on reports.
Bugnet captures bugs from all affected players, revealing the true number versus the few who report. The gap between problems experienced and reported is a sign players are hitting bugs you can't see, and it's only visible if you capture bugs automatically (showing the true affected-player count versus the small fraction who report), which exposes how many bugs players hit that you'd miss relying on reports.
Crashes You Can't Reproduce
A sign is crashes or bugs you can't reproduce on your own setup, players report them but they never happen for you. These are bugs players hit in conditions you don't have (device-specific, edge-case), so they're hitting bugs you can't see on your machine, in the field conditions you don't replicate.
Bugnet captures crashes with device context from the field, so the bugs players hit in conditions you don't have are visible. Crashes you can't reproduce are a sign players are hitting bugs you can't see (in field conditions you don't replicate), and capturing them from the field with context is how you see them, the captured device and conditions reveal the bugs players hit that are invisible on your machine.
Watch for unexplained churn and bad reviews, a gap between problems experienced and reported, and crashes you can't reproduce. Most players who hit a bug never report it, so they hit bugs you can't see without field capture.