On the iOS application you also need a 'cancel' button on the chat box. If you change your mind after bringing it up, you have to say something - I usually just type a '.' then 'enter' to get out.
It doesn't necessarily mean that they logged themselves off - BBO has a habit of indiscriminately booting players off, who then have to scrabble to get back.
On the contrary - bridge is a social game, you can get kicked out of a club for not being nice. My ignore list is full of posters who have need for politeness.
Whilst we're on the subject, can the typed abbreviations be converted to full when chat audio is on? It does it for 'thx', but things like glp, typ, ty, brb, wpo come out as just the letters.
The delay in making a bid may be due to the opps. not responding to a request for clarification. You need some way of attributing delay which takes that into account.
A slightly more involved method - which works if they are completely untraceable is to search for people in the same club who might be playing with them. Then you can message them to get comtact details, or look at whom they are sharing tables with.
I use an old iPad using ios 10.3.4 As far as I recall (it was awhile ago I tested everything) the only thing it fails to do is access some of the hosting menu options when trying to run a teams game. Then I have to revert to a laptop.
Underneath the first 'Start a table' there is Relaxed Bridge Club and Main Bridge Club. These are the 2 locations your table will be placed depending on which button you press. It is probably worth watching a few tables in the main bridge club and observing the temperment of the players. When BBO kicks one of your group off due to problems, the type of player you get landed with in their place will depend on which club you are in.