This is normally caused by the character being logged in from another (or the same) location and causes the server to forcibly disconnect you.
Make sure your bot is running twice for example.

I'm not seeing any issue on any of the 7 AO bots I'm operating.

curl vs sockets won't affect this in any way. It only involves how the bot connects to the webservers for XML items using either the high speed curl library (native C code) or sockets (interpreted php).
If the connection times out using curl, it will time out using sockets and vice versa.

The thing to keep in mind would be that the firewall/antidos systems at Funcom does not distinguish between connections to the AO chatservers and the webserver afaik. But if this was the reason for the bot being booted from the chatserver, it should affect all the bots you run provided they are using the same IP.

Other than that, I don't know what to tell you as there is no sane reason for this to affect only the one bot unless someone is flooding it somehow or causing it to flood/output oversized blobs which shouldn't be possible for any shipped modules at least.