Why is BYE not coming from Asterisk?

Question

Asterisk

I use Asterisk and a webphone on jsSIP, the calls work fine, if we end the call everything is OK, but if we close the browser, the connection is lost, but Asterisk does not close the channel and does not send BYE, I set all the timeouts, qualify is worth it, the asterisk marks the peer as UNREACHABLE, but the channel still does not close.
Asterisk 16.12.0
chan_sip