Change in network connectivity may lead to concurrent sync task; then stop working

Sometime, chatty/libcmatrix start two concurrents sync tasks, this works for a while and then chatty stop doesn't sync with the server anymore.

In the logs, we can have:

12:32:51.1784            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Stop sync
12:32:51.1846    chatty-ma-account[ 2613]:   TRACE: client_status_changed_cb():620: status changed, connected: false, user: @t##y:a#####d.fr
12:32:52.6014            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Stop sync
13:29:08.5137            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Stop sync
13:29:09.5983            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Stop sync
13:29:10.2656            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Stop sync
13:29:11.9521            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Start sync
13:29:13.6004            cm-client[ 2613]:   DEBUG: (0xaaaacd7715a0) Start sync

When that happen, chatty still sync new matrix messages for a while, and then that stop working. Even trying to change the network connectivity doesn't bring back the connection. Only restarting chatty works.