Somehow between multiple soft resets I was able to get the esp8266 stuck in a state where sta.isconnect() returns False and s.status() returns network.STAT_CONNECTING forever.
However it was perfectly connected and I could use the webrepl.
Only a disconnect followed by a connect fixed that.

I know that without a reproducable testcase this issue might be worthless, in which case feel free to close it. But maybe someone familiar with the esp8266 network code can see a possibility for this to happen now that he has the information.

(Well I can "reproduce" it by doing multiple resets in a wdt interrupt routine and repl reconnects but I can't provide a real testcase at the moment)