This number represents the total active client connections that are currently routed through the tunnel between the container and Cloudflare's edge proxy. Each container can maintain up to four active connections, but this can fluctuate during retries, for example, temporarily increasing the count. Fluctuations are normal and can be caused by things like:
Cloudflare maintenance or updates.
Network disruptions, causing reconnection attempts.
Changes in traffic volume, leading to more connections.
For more information on the Tines tunnel, read here.