“Issues” are not bugs. But contains bugs. Imagine we have a perfect software for Macs, zero known bugs. Then Apple releases a MacOS Catalina and it starts to crash. People start to log “Issues” they never saw before, but now they see. Same for a new iOS, or new Android, many things.
Also, the software we are talking about have 2 stable platforms (iOS and Android), one unstable (Web), 3 Alphas (under heavy development Mac, Windows and Linux) and one “secret”, Fuchsia (Secret because we don’t know how Google classifies its maturity right now, its kind of “secret”). All those, per se, not stable, being developed, are a factory of monthly “issues”. E.g. Issue: “Previous releases were touch enabled only, now, with desktop platforms, we need also handle mouse interfaces”. This “issue” will be split in many other issues to enable mouse handling in diverse platforms.